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devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Get started with Firebase</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Add Firebase to an app</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ios/setup" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/android/setup" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/web/setup" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Web</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Add Firebase to a game</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/games/setup" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cpp/setup" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>C++</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/unity/setup" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Unity</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/admin/setup" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Add Firebase to a server</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Use Firebase with a framework</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/flutter/setup" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Flutter</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/api/workflow_set-up-and-manage-project" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Set up projects programmatically</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Manage your Firebase projects</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/learn-more" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Understand Firebase projects</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/locations" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Select locations for your project</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/multiprojects" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Configure multiple projects</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/api-keys" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Learn about API keys for Firebase</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/pwa" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use Firebase in PWAs</span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/bigquery-export" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Export project data to BigQuery</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/manage-installations" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage Firebase installations</span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/import-segments" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Import segments</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Manage projects programmatically</span></div></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/api/workflow_set-up-and-manage-project" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use the REST API</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Use the Admin SDK</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/admin/node/admin.projectManagement" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Node.js</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/admin/java/reference/com/google/firebase/projectmanagement/package-summary" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Java</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/admin/python/firebase_admin.project_management" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Python</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/provisioning/configure-oauth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Configure OAuth identity providers for Firebase Auth</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Manage project access (IAM)</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/iam/overview" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Roles</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/iam/roles" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/iam/roles-basic" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Owner, Editor, Viewer roles</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Firebase predefined roles</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/iam/roles-predefined" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/iam/roles-predefined-all-products" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Firebase-level roles</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/iam/roles-predefined-category" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Product-category roles</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/iam/roles-predefined-product" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Product-level roles</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/iam/roles-custom" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Custom roles</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/projects/iam/permissions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Permissions</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Platforms and frameworks</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>iOS</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ios/link-firebase-static-dynamic" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Link Firebase dependencies statically or dynamically</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ios/app-store-data-collection" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Prepare for Apple App Store data disclosure requirements</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Android</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/android/learn-more" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Learn about Android + Firebase</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/android/android-play-services" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Dependencies of Firebase Android SDKs on Google Play services</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/android/integrate-play-games" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Integrate with your Play Games Services project</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Web</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/web/environments-js-sdk" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Supported environments for the Firebase JS SDK</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion devsite-nav-beta"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Prototype and test with Emulator Suite</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/emulator-suite" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Connect your app and prototype</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/emulator-suite/connect_and_prototype" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/emulator-suite/connect_auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Connect to the Authentication emulator</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/emulator-suite/connect_rtdb" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Connect to the Realtime Database emulator</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/emulator-suite/connect_firestore" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Connect to the Cloud Firestore emulator</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/emulator-suite/connect_functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Connect to the Cloud Functions emulator</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/emulator-suite/install_and_configure" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Install, configure and integrate</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Analytics</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/get-started" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/events" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Log Events</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/user-properties" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Set User Properties</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/debugview" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Debug Events</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/screenviews" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Track Screens</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/userid" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Set a User ID</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/measure-ecommerce" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Measure Ecommerce</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/webview" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use in a WebView</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/extend-with-functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Extend with Cloud Functions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/configure-data-collection" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Configure Data Collection and Usage</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/errors" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Error Codes</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>C++</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/cpp/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/cpp/events" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Log Events</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/cpp/properties" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Set User Properties</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Unity</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/unity/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/unity/events" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Log Events</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/analytics/unity/properties" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Set User Properties</span></a></li></ul></devsite-expandable-nav></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion devsite-nav-beta"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Extensions</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/extensions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Use an extension in your project</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/extensions/overview-use-extensions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/extensions/install-extensions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Install an extension</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/extensions/manage-installed-extensions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage installed extensions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/extensions/permissions-granted-to-extension" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Permissions granted to an extension</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-divider devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Build</span></div></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Authentication</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/where-to-start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Where do I start?</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/users" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Users in Firebase Projects</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>iOS</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/firebaseui" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Sign in with a pre-built UI</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/manage-users" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage Users</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/password-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Password Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/email-link-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Email Link Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/google-signin" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Google Sign-In</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/facebook-login" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Facebook Login</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/apple" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Sign in with Apple</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/twitter-login" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Twitter Login</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/github-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>GitHub</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/microsoft-oauth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Microsoft</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/yahoo-oauth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Yahoo</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/game-center" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Game Center Sign-in</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/phone-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Phone Number</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/custom-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use a Custom Auth System</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/anonymous-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Anonymous Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/single-sign-on" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Enabling cross-app authentication with shared iOS Keychain</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/account-linking" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Link Multiple Auth Providers</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/passing-state-in-email-actions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Passing State in Email Actions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/ios/errors" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Handle Errors</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Android</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/firebaseui" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Sign in with a pre-built UI</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started with the Firebase SDK</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/manage-users" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage Users</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/password-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Password Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/email-link-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Email Link Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/google-signin" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Google Sign-In</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/facebook-login" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Facebook Login</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/apple" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Sign in with Apple</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/twitter-login" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Twitter</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/github-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>GitHub</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/microsoft-oauth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Microsoft</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/yahoo-oauth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Yahoo</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/play-games" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Play Games Sign-in</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/phone-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Phone Number</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/custom-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use a Custom Auth System</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/anonymous-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Anonymous Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/account-linking" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Link Multiple Auth Providers</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/android/passing-state-in-email-actions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Passing State in Email Actions</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Web</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/firebaseui" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Sign in with a pre-built UI</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/manage-users" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage Users</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/password-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Password Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/email-link-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Email Link Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/google-signin" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Google Sign-In</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/facebook-login" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Facebook Login</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/apple" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Sign in with Apple</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/twitter-login" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Twitter</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/github-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>GitHub</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/microsoft-oauth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Microsoft</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/yahoo-oauth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Yahoo</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/phone-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Phone Number</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/custom-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use a Custom Auth System</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/anonymous-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Anonymous Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/account-linking" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Link Multiple Auth Providers</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/cordova" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>OAuth Sign-In for Cordova</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/auth-state-persistence" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Auth State Persistence</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/passing-state-in-email-actions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Passing State in Email Actions</span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/web/service-worker-sessions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Service Worker Sessions</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>C++</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/manage-users" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage Users</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/password-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Password Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/google-signin" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Google Sign-in</span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/play-games" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Play Games Sign-in</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/github-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>GitHub</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/facebook-login" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Facebook Login</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/apple" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Sign in with Apple</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/twitter-login" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Twitter Login</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/microsoft-oauth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Microsoft</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/yahoo-oauth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Yahoo</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/phone-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Phone Number</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/custom-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use a Custom Auth System</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/anonymous-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Anonymous Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/cpp/account-linking" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Link Multiple Auth Providers</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Unity</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/manage-users" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage Users</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/password-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Password Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/google-signin" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Google Sign-in</span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/play-games" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Play Games Sign-in</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/github-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>GitHub Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/facebook-login" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Facebook Login</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/apple" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Sign in with Apple</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/twitter-login" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Twitter Login</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/microsoft-oauth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Microsoft</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/yahoo-oauth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Yahoo</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/phone-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Phone Number</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/custom-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use a Custom Auth System</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/anonymous-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Anonymous Authentication</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/unity/account-linking" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Link Multiple Auth Providers</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Admin</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/admin" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/admin/manage-users" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage Users</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/admin/import-users" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Import Users</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/admin/create-custom-tokens" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Create Custom Tokens</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/admin/verify-id-tokens" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Verify ID Tokens</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/admin/manage-sessions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage User Sessions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/admin/manage-cookies" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage Session Cookies</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/admin/custom-claims" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Control Access with Custom Claims</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/admin/email-action-links" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Generating Email Action Links</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/admin/errors" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Errors</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/admin/migrate-admin" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Migration Guide</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/custom-email-handler" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Customize the Email Action Handler</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/extend-with-functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Extend with Cloud Functions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/case-studies" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Case Studies</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/auth/limits" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Usage Limits</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Realtime Database</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/rtdb-vs-firestore" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Choose a Database</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>iOS</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/ios/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/ios/structure-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Structure Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/ios/read-and-write" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Read and Write Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/ios/lists-of-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Work with Lists of Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/ios/offline-capabilities" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Enable Offline Capabilities</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Android</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/android/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/android/structure-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Structure Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/android/read-and-write" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Read and Write Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/android/lists-of-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Work with Lists of Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/android/offline-capabilities" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Enable Offline Capabilities</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Web</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/web/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/web/structure-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Structure Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/web/read-and-write" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Read and Write Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/web/lists-of-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Work with Lists of Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/web/offline-capabilities" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Enable Offline Capabilities</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Admin</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/admin/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/admin/structure-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Structure Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/admin/save-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Save Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/admin/retrieve-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Retrieve Data</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>REST</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/rest/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/rest/structure-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Structure Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/rest/save-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Save Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/rest/retrieve-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Retrieve Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/rest/auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Authenticate REST Requests</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>C++</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/cpp/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/cpp/structure-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Structure Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/cpp/save-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Save Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/cpp/retrieve-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Retrieve Data</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Unity</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/unity/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/unity/structure-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Structure Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/unity/save-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Save Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/unity/retrieve-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Retrieve Data</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Security & Rules</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/security" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Understand Rules</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/security/get-started" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/security/core-syntax" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Structure Security Rules</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/security/rules-conditions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Write Conditions for Security Rules</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/security/indexing-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Index Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/rest/app-management" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage Rules via REST</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Usage and Performance</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/usage/billing" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Understand Billing</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/usage/limits" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Realtime Database Limits</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/usage/monitor-usage" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Monitor Database Usage</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/usage/monitor-performance" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Monitor Database Performance</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/usage/sharding" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Scale with Multiple Databases</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/usage/profile" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Profile Your Database</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/usage/optimize" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Optimize Database Performance</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/backups" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Automated Backups</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/extend-with-functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Extend with Cloud Functions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/database/video-series" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Video series: Firebase for SQL Developers</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Cloud Firestore</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/quickstart" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Understand Cloud Firestore</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/rtdb-vs-firestore" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Compare Cloud Firestore and Realtime Database</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/data-model" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Data model</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/manage-data/data-types" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Data types</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/client/libraries" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>SDKs and client libraries</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/query-data/index-overview" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Index types</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/locations" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Database locations</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Add and manage data</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/manage-data/structure-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Structure data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/manage-data/add-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Add data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/manage-data/transactions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Transactions and batched writes</span></a></li><li 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href="/web/20210124195105/https://firebase.google.com/docs/firestore/manage-data/move-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Move data between projects</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Read data</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/query-data/get-data" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get data once</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/query-data/listen" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Listen for realtime updates</span></a></li><li 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href="/web/20210124195105/https://firebase.google.com/docs/firestore/query-data/indexing" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage indexes</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Secure and validate data</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/security/overview" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/security/get-started" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/security/rules-structure" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Structure Security Rules</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/security/rules-conditions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Writing conditions for Security Rules</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/security/insecure-rules" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Fix insecure rules</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/security/test-rules-emulator" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test your Security Rules</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/security/rules-query" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Securely query data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/security/rules-fields" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Control access per field</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Solutions</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/solutions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/solutions/aggregation" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Aggregation Queries</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/solutions/counters" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Distributed counters</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/solutions/search" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Full-text search</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/solutions/presence" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Build presence</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/solutions/role-based-access" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Secure data access for users and groups</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/solutions/delete-collections" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Delete data with a callable Cloud Function</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/solutions/schedule-export" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Schedule data exports</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/solutions/shard-timestamp" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Sharded timestamps</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/solutions/geoqueries" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Geo queries</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/solutions/automate-database-create" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Automating database creation</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/solutions/index-map-field" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Reduce index costs with map fields</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Usage, limits, and pricing</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/quotas" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Usage and limits</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/monitor-usage" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Monitor usage</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/pricing" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Understand Cloud Firestore billing</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/billing-example" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Example Cloud Firestore costs</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/storage-size" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Understand storage size calculations</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/best-practices" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Best practices for Cloud Firestore</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Cloud Firestore integrations</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/use-rest-api" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use the Cloud Firestore REST API</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/firestore-for-rtdb" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use Cloud Firestore and Realtime Database</span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/extend-with-functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Extend with Cloud Functions</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/library-integrations" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Third-party library integrations</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>API reference</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/android/com/google/firebase/firestore/package-summary" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/swift/firebasefirestore/api/reference/Classes" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS — Swift</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/ios/firebasefirestore/api/reference/Classes" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS — Objective-C</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/js/firebase.firestore" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Web</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/functions/providers_firestore_" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Cloud Functions</span></a></li><li class="devsite-nav-item"><a href="//web.archive.org/web/20210124195105/https://googleapis.dev/nodejs/firestore/latest/" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Node.js</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/admin/java/reference/com/google/firebase/cloud/FirestoreClient" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Java</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/admin/python/firebase_admin.firestore" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Python</span></a></li><li class="devsite-nav-item"><a href="//web.archive.org/web/20210124195105/https://godoc.org/cloud.google.com/go/firestore" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Go</span></a></li><li class="devsite-nav-item"><a href="//web.archive.org/web/20210124195105/https://googleapis.github.io/google-cloud-dotnet/docs/Google.Cloud.Firestore/" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>C#</span></a></li><li class="devsite-nav-item"><a href="//web.archive.org/web/20210124195105/https://googleapis.github.io/google-cloud-php/#/docs/cloud-firestore/latest/firestore/readme" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>PHP</span></a></li><li class="devsite-nav-item"><a href="//web.archive.org/web/20210124195105/https://googleapis.github.io/google-cloud-ruby/docs/google-cloud-firestore/latest/Google/Firestore/V1beta1" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Ruby</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/reference/rest" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>REST</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/reference/rpc" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>RPC</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Samples</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/client/samples-ios" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/client/samples-android" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/firestore/client/samples-web" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Web</span></a></li></ul></devsite-expandable-nav></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Storage</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>iOS</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/ios/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/ios/create-reference" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Create a Reference</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/ios/upload-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Upload Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/ios/download-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Download Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/ios/file-metadata" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use File Metadata</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/ios/delete-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Delete Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/ios/list-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>List Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/ios/handle-errors" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Handle Errors</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Android</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/android/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/android/create-reference" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Create a Reference</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/android/upload-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Upload Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/android/download-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Download Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/android/file-metadata" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use File Metadata</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/android/delete-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Delete Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/android/list-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>List Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/android/handle-errors" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Handle Errors</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Web</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/web/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/web/create-reference" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Create a Reference</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/web/upload-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Upload Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/web/download-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Download Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/web/file-metadata" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use File Metadata</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/web/delete-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Delete Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/web/list-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>List Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/web/handle-errors" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Handle Errors</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Admin</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/admin/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>C++</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/cpp/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/cpp/create-reference" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Create a Reference</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/cpp/upload-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Upload Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/cpp/download-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Download Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/cpp/file-metadata" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use File Metadata</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/cpp/delete-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Delete Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/cpp/handle-errors" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Handle Errors</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Unity</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/unity/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/unity/create-reference" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Create a Reference</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/unity/upload-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Upload Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/unity/download-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Download Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/unity/file-metadata" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use File Metadata</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/unity/delete-files" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Delete Files</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/unity/handle-errors" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Handle Errors</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Security & Rules</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/security" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Understand Security</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/security/get-started" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/security/core-syntax" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Structure Security Rules</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/security/rules-conditions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Write Conditions for Security Rules</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/monitor-storage" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Monitor activity</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/extend-with-functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Extend with Cloud Functions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/storage/gcp-integration" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Integrate with Google Cloud</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Hosting</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/use-cases" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>What can you do with Firebase Hosting?</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/quickstart" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started</span></a></li><li class="devsite-nav-item devsite-nav-new"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/test-preview-deploy" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test, preview, then deploy</span><span class="devsite-nav-icon material-icons" data-icon="new" data-title="New!" aria-hidden="true"></span></a></li><li class="devsite-nav-item devsite-nav-new"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/github-integration" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Deploy via GitHub pull requests</span><span class="devsite-nav-icon material-icons" data-icon="new" data-title="New!" aria-hidden="true"></span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/multisites" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Share project resources across multiple sites</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/custom-domain" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Connect a custom domain</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/full-config" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Configure hosting behavior</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/i18n-rewrites" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Configure i18n rewrites</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/reserved-urls" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Add SDKs using reserved URLs</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Serve dynamic content and host microservices</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/serverless-overview" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use Cloud Functions for Firebase</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/cloud-run" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use Cloud Run</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/manage-cache" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage cache behavior</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/manage-hosting-resources" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage live & preview channels, releases, and versions</span></a></li><li class="devsite-nav-item devsite-nav-new"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/web-request-logs-and-metrics" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Monitor web request data with Cloud Logging</span><span class="devsite-nav-icon material-icons" data-icon="new" data-title="New!" aria-hidden="true"></span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/usage-quotas-pricing" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Usage, quotas, and pricing</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/hosting/api-deploy" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Deploy using the REST API</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Cloud Functions</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/use-cases" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>What can I do with Cloud Functions?</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/get-started" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/beta-v1-diff" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Upgrade to v1.0+ from beta</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Call functions directly</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/callable" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Call functions from your app</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/http-events" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Call functions via HTTP requests</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/schedule-functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Run functions on a schedule</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Trigger background functions</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/firestore-events" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Cloud Firestore triggers</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/database-events" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Realtime Database triggers</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/rc-events" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Remote Config triggers</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/auth-events" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Authentication triggers</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/analytics-events" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Analytics triggers</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item devsite-nav-deprecated"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/crashlytics-events" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Crashlytics triggers</span><span class="devsite-nav-icon material-icons" data-icon="deprecated" data-title="Deprecated" aria-hidden="true"></span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/gcp-storage-events" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Cloud Storage triggers</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/pubsub-events" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Pub/Sub triggers</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/test-lab-events" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test Lab triggers</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Write functions</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/manage-functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage deployment and runtime options</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/typescript" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Write functions in TypeScript</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/terminate-functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Sync, async, and promises</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/retries" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Retry asynchronous functions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/config-env" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Environment configuration</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/organize-functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Organize functions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/handle-dependencies" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Handling dependencies</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/networking" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Optimizing networking</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/tips" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Tips & tricks</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Test functions</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/local-emulator" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Run functions locally</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/unit-testing" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Unit testing functions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/local-shell" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test functions interactively</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Monitor functions</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/writing-and-viewing-logs" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Write and view logs</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/reporting-errors" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Report errors</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/monitored-metrics" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>View monitored metrics</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>API Reference</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Firebase SDK for Cloud Functions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/functions/test" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test SDK</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/callable-reference" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Protocol specification for https.onCall</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/video-series" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Video Series: learn Cloud Functions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/functions-and-firebase" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Cloud Functions and Firebase</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/locations" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Cloud Functions locations</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/functions/quotas" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Quotas and limits</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion devsite-nav-beta"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Machine Learning</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/codelabs" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Codelabs</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Vision</span></div></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Recognize text</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/recognize-text" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/ios/recognize-text" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/android/recognize-text" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Label images</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/label-images" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/ios/label-images" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/android/label-images" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Recognize landmarks</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/recognize-landmarks" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/ios/recognize-landmarks" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/android/recognize-landmarks" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>AutoML Vision Edge</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/automl-image-labeling" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/train-image-labeler" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Train image labeling models</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Label images with your models</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/ios/label-images-with-automl" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/android/label-images-with-automl" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/train-object-detector" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Train object detection models</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Detect objects with your models</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/ios/detect-objects-with-automl" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/android/detect-objects-with-automl" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/migrate-automl-datasets" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Migrate datasets</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Custom Models</span></div></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Use a custom model</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/use-custom-models" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/ios/use-custom-models" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/android/use-custom-models" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/manage-hosted-models" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Deploy & manage custom models</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Migrate from the legacy API</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/ios/migrate-from-legacy-api" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/android/migrate-from-legacy-api" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Advanced Topics</span></div></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>A/B test two versions of a model</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/ios/ab-test-models" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/android/ab-test-models" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Prepare for Production</span></div></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Protect your Cloud credentials</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/ios/secure-api-key" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml/android/secure-api-key" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Legacy Documentation</span></div></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>ML Kit for Firebase</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Vision</span></div></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Recognize text</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/recognize-text" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/recognize-text" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/recognize-text" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Detect faces</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/detect-faces" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/face-detection-concepts" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Concepts</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/detect-faces" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/detect-faces" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Scan barcodes</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/read-barcodes" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/read-barcodes" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/read-barcodes" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Label images</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/label-images" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/label-images" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/label-images" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Detect and track objects</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/object-detection" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/detect-objects" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/detect-objects" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Recognize landmarks</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/recognize-landmarks" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/recognize-landmarks" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/recognize-landmarks" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>AutoML Vision Edge</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/automl-image-labeling" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/train-image-labeler" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Train image labeling models</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Label images with your models</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/label-images-with-automl" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/label-images-with-automl" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/migrate-automl-datasets" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Migrate datasets</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Natural Language</span></div></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Identify the language of text</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/identify-languages" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/identify-languages" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/identify-languages" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Translate text</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/translation" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/translate-text" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/translate-text" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/translation-terms" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Usage guidelines</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Generate smart replies</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/generate-smart-replies" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/generate-smart-replies" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/generate-smart-replies" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Custom Models</span></div></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Use a custom model</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/use-custom-models" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/use-custom-models" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/use-custom-models" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/manage-hosted-models" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage hosted custom models</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Use a custom TensorFlow Lite build</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/use-custom-tflite" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/use-custom-tflite" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Advanced Topics</span></div></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>A/B test two versions of a model</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/ab-test-models" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/ab-test-models" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Prepare for Production</span></div></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Reduce app package size</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/reduce-app-size" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Protect your Cloud credentials</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/ios/secure-api-key" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ml-kit/android/secure-api-key" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li></ul></devsite-expandable-nav></li></ul></devsite-expandable-nav></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Security Rules</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/rules" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/rules/get-started" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Understand Security Rules</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/rules/rules-language" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Security Rules language</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/rules/rules-behavior" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>How Security Rules work</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/rules/rules-and-auth" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Security Rules and Firebase Authentication</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Write Security Rules</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/rules/basics" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Basic Security Rules</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/rules/insecure-rules" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Avoid insecure rules</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/rules/data-validation" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Data validation</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Test Security Rules</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/rules/emulator-setup" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Set up the emulator</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/rules/unit-tests" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Build unit tests</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/rules/emulator-reports" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Generate test reports</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/rules/simulator" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Quickly validate Security Rules</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/rules/manage-deploy" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage and deploy Security Rules</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-divider devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Release & Monitor</span></div></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Crashlytics</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/crashlytics" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/crashlytics/get-started" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/crashlytics/start-using-analytics" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get metrics with Google Analytics</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/crashlytics/test-implementation" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test your implementation</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/crashlytics/customize-crash-reports" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Customize crash reports</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/crashlytics/get-deobfuscated-reports" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get deobfuscated crash reports</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/crashlytics/ndk-reports" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Android NDK crash reports</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/crashlytics/velocity-alerts" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Customize velocity alerts</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/crashlytics/bigquery-export" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Export data to BigQuery</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/crashlytics/troubleshooting" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Troubleshooting</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>From Fabric to Firebase</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/crashlytics/migration-post-linking" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Steps after migrating your app</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/crashlytics/upgrade-sdk" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Upgrade to the Firebase Crashlytics SDK</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/crashlytics/switch-to-analytics" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Switch from Answers to Analytics</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Performance Monitoring</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Get started</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/get-started-ios" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/get-started-android" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/get-started-web" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Web</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Learn about automatically collected data</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/app-start-foreground-background-traces" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>App start, foreground, background (iOS & Android)</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/screen-traces" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Screen rendering (iOS & Android)</span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/page-load-traces" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Page loading (web)</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/network-traces" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>HTTP/S network requests</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Customize data collection and aggregation</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/custom-code-traces" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Add monitoring for specific code</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/custom-network-traces" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Add monitoring for specific network requests</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/custom-url-patterns" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Create custom URL patterns</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/disable-sdk" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Disable Performance Monitoring</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Track, view, and filter data</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/console" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview of the console</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/attributes" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Filter data using attributes</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/issue-management" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>View performance issues</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/bigquery-export" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Export data to BigQuery</span></a></li><li class="devsite-nav-item devsite-nav-break"></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/perf-mon/troubleshooting" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Troubleshooting & FAQ</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Test Lab</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>iOS</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/ios/firebase-console" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test with the Firebase console</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/ios/command-line" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test with the gcloud CLI</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/game-loop" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Run a Game Loop test</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/ios/analyzing-results" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Analyze test results</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/ios/available-testing-devices" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test on available devices</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Android</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/android/overview" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/android/firebase-console" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test with the Firebase console</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/android/command-line" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test with the gcloud CLI</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/android/continuous" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test with CI systems</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/android/android-studio" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test with Android Studio</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/android/analyzing-results" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Analyze test results</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/android/available-testing-devices" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test on available devices</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/android/instrumentation-test" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Run an instrumentation test</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/android/robo-ux-test" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Run a Robo test</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/android/game-loop" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Run a Game Loop test</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/android/test-screenshots" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Take screenshots in a test</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/android/avds" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test with virtual devices</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-new"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/troubleshooting" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Troubleshooting</span><span class="devsite-nav-icon material-icons" data-icon="new" data-title="New!" aria-hidden="true"></span></a></li><li class="devsite-nav-item devsite-nav-new"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/usage-quotas-pricing" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Usage, quotas, & pricing</span><span class="devsite-nav-icon material-icons" data-icon="new" data-title="New!" aria-hidden="true"></span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/extend-with-functions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Extend with Cloud Functions</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>REST API reference</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/reference/testing/rest" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Testing (submit test & monitor)</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/test-lab/reference/toolresults/rest" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>ToolResults (retrieve results)</span></a></li></ul></devsite-expandable-nav></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion devsite-nav-beta"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>App Distribution</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-distribution" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-distribution/manage-testers" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage testers</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-distribution/troubleshooting" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Troubleshooting</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Set up for testers</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-distribution/ios/set-up-for-testing" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-distribution/android/set-up-for-testing" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Distribute iOS apps</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-distribution/ios/distribute-console" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use the Firebase console</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-distribution/ios/distribute-cli" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use the Firebase CLI</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-distribution/ios/distribute-fastlane" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use fastlane</span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/app-distribution/set-up-alerts" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Set up in-app alerts</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Distribute Android apps</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-distribution/android/distribute-console" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use the Firebase console</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-distribution/android/distribute-cli" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use the Firebase CLI</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-distribution/android/distribute-fastlane" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use fastlane</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-distribution/android/distribute-gradle" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use Gradle</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-divider devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Engage</span></div></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Predictions</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/predictions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/predictions/get-started" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/predictions/predefined-predictions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Churn and spend predictions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/predictions/bigquery-export" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Export prediction data to BigQuery</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Use case examples</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/predictions/use-cases/prevent-churn" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Prevent churn</span></a></li><li class="devsite-nav-item devsite-nav-break"></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Legacy Predictions (deprecated)</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/predictions/v1" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/predictions/v1/get-started" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Use Cases</span></div></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/predictions/use-cases/prevent-churn" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Prevent Churn</span></a></li><li class="devsite-nav-item devsite-nav-break"></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/predictions/v1/explore-predictions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Explore Prediction Results</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/predictions/v1/bigquery-export" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Export Prediction Data to BigQuery</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/predictions/v1/predefined-predictions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Churn and Spend Predictions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/predictions/v1/risk-profiles" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Risk Tolerance and Model Performance</span></a></li></ul></devsite-expandable-nav></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion devsite-nav-beta"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>A/B Testing</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ab-testing" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ab-testing/abtest-config" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Create Remote Config Experiments with A/B Testing</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ab-testing/abtest-with-console" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Create Messaging Experiments with A/B Testing</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ab-testing/abtest-inappmessaging" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Create In-App Messaging Experiments with A/B Testing</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/ab-testing/video-series" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Video Series: Learn A/B Testing</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Cloud Messaging</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/fcm-architecture" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>FCM Architectural Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/concept-options" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>About FCM messages</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>iOS</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/ios/client" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Set up an iOS client</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/ios/certs" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Configuring APNs with FCM</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/ios/first-message" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send a test message</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/ios/send-multiple" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send messages to multiple devices</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/ios/send-image" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send an image in the notification payload</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/ios/receive" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Receive messages</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/ios/topic-messaging" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send messages to topics</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/ios/device-group" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send to device groups</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/ios/send-with-console" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send messages with the Firebase Console</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Android</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/android/client" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Set up an Android client</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/android/first-message" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send a test message</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/android/send-multiple" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send messages to multiple devices</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/android/send-image" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send an image in the notification payload</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/android/receive" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Receive messages</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/android/topic-messaging" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send messages to topics</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/android/device-group" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send to device groups</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/android/upstream" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send upstream messages</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/android/send-with-console" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send messages with the Firebase Console</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>C++</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/cpp/client" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Set up a C++ client</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/cpp/receive" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Receive messages</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/cpp/topic-messaging" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send messages to topics</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/cpp/device-group" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send to device groups</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/cpp/upstream" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send upstream messages</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/cpp/send-with-console" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send messages with the Firebase Console</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Unity</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/unity/client" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Set up a Unity client</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/unity/receive" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Receive messages</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/unity/topic-messaging" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send messages to topics</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/unity/device-group" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send to device groups</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/unity/upstream" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send upstream messages</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/unity/send-with-console" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send messages with the Firebase Console</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Web (JavaScript)</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/js/client" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Set up a JavaScript client</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/js/first-message" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send a test message</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/js/send-multiple" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send messages to multiple devices</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/js/receive" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Receive messages</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/js/topic-messaging" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send messages to topics</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/js/device-group" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send to device groups</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/js/send-with-console" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Send messages with the Firebase Console</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/js/case-studies" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Case studies</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Server environments</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/server" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Your server environment and FCM</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/migrate-v1" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Migrate to the HTTP v1 API</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/auth-server" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Authorize send requests</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/send-message" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Build send requests</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/receive-upstream" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Receive upstream messages</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/manage-topics" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manage topics from the server</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/cloud-messaging/understand-delivery" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Understanding message delivery</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion devsite-nav-beta"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>In-App Messaging</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/in-app-messaging" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/in-app-messaging/get-started" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/in-app-messaging/explore-use-cases" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Explore use cases</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/in-app-messaging/compose-campaign" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Compose a campaign</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/in-app-messaging/modify-message-behavior" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Modify message behavior</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/in-app-messaging/customize-messages" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Customize messages</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Remote Config</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>What can I do with Remote Config?</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config/use-cases" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Remote Config use cases</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Key concepts and strategies</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config/parameters" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Parameters and conditions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config/templates" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Templates and versioning</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config/loading" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Config loading strategies</span></a></li><li class="devsite-nav-item devsite-nav-beta"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config/propagate-updates-realtime" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Propagate updates in real time</span><span class="devsite-nav-icon material-icons" data-icon="beta" data-title="Beta" aria-hidden="true"></span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config/config-analytics" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Remote Config and Analytics</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>iOS</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config/use-config-ios" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started with Remote Config on iOS</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Android</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config/use-config-android" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started with Remote Config on Android</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Web (JavaScript)</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config/use-config-web" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started with Remote Config on Web</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>C++</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config/use-config-cpp" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use Remote Config with C++</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Unity</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config/use-config-unity" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use Remote Config with Unity</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config/automate-rc" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Modify Remote Config programmatically</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>API reference</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/remote-config/rest" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>REST API reference</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/remote-config/condition-reference" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Conditional expression reference</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/android/com/google/firebase/remoteconfig/package-summary" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android SDK reference</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/swift/firebaseremoteconfig/api/reference/Classes" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS Swift SDK reference</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/ios/firebasecore/api/reference/Classes" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS Obj-C SDK reference</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/unity/namespace/firebase/remote-config" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Unity reference</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/reference/cpp/namespace/firebase/remote-config" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>C++ reference</span></a></li></ul></devsite-expandable-nav></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Dynamic Links</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Use Cases</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/use-cases" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Overview</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/use-cases/web-to-app" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Convert Web Users To App Users</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/use-cases/user-to-user" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Invite Users to Your App</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/use-cases/rewarded-referral" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Reward User Referrals</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/operating-system-integrations" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Operating System Integrations</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Create Dynamic Links</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/create-links" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/ios/create" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/android/create" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/cpp/create" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>C++</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/unity/create" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Unity</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/rest" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>REST</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/create-manually" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Manual URL Construction</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Receive Dynamic Links</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/ios/receive" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/android/receive" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Android</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/cpp/receive" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>C++</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/unity/receive" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Unity</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/custom-domains" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use a Custom Domain</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/analytics" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>View Analytics Data</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/debug" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Debug Dynamic Links</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/dynamic-links/link-previews" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Link Previews & Social Metadata</span></a></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item devsite-nav-expandable devsite-nav-accordion"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Google AdMob</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/admob" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/admob/ios/quick-start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started for iOS</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/admob/android/quick-start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started for Android</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/admob/analytics-and-firebase" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Use Analytics and Firebase with AdMob apps</span></a></li><li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"><span class="devsite-nav-text" tooltip>Use AdMob in a game</span></div></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>C++</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/admob/cpp/quick-start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/admob/cpp/cocos2d-x" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Cocos2d-x</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/admob/cpp/rewarded-video" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Rewarded video</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Unity</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item devsite-nav-external"><a href="//web.archive.org/web/20210124195105/https://developers.google.com/admob/unity/start" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get started</span><span class="devsite-nav-icon material-icons" data-icon="external" data-title="External" aria-hidden="true"></span></a></li></ul></devsite-expandable-nav></li></ul></devsite-expandable-nav></li> <li class="devsite-nav-item 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class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Introduction</span></a></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>iOS</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-indexing/ios/app" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-indexing/ios/test" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test Your Implementation</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-indexing/ios/measure" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Enhance Search Performance</span></a></li></ul></devsite-expandable-nav></li><li class="devsite-nav-item devsite-nav-expandable"><devsite-expandable-nav collapsed> <a class="devsite-nav-toggle" aria-hidden="true"></a><div class="devsite-nav-title devsite-nav-title-no-path" tabindex="0" role="button"><span class="devsite-nav-text" tooltip>Android</span></div><ul class="devsite-nav-section"><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-indexing/android/app" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Get Started</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-indexing/android/public-content" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Refine Public Content Indexing</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-indexing/android/log-actions" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Log User Actions</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-indexing/android/test" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Test Your Implementation</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-indexing/android/measure" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Enhance Search Performance</span></a></li><li class="devsite-nav-item"><a href="/web/20210124195105/https://firebase.google.com/docs/app-indexing/android/migrate" class="devsite-nav-title"><span class="devsite-nav-text" tooltip>Migrate to the Latest API</span></a></li></ul></devsite-expandable-nav></li></ul></devsite-expandable-nav></li> </ul> <ul class="devsite-nav-list" menu="Products" aria-label="Side menu" hidden> <li class="devsite-nav-item"> <a href="/web/20210124195105/https://firebase.google.com/products-build" class="devsite-nav-title gc-analytics-event " data-category="Site-Wide Custom Events" data-label="Responsive Tab: Build" track-type="navMenu" track-metadata-eventdetail="globalMenu" track-metadata-position="nav" track-name="build"> <span class="devsite-nav-text" tooltip> Build </span> </a> </li> <li class="devsite-nav-item"> <a href="/web/20210124195105/https://firebase.google.com/products-release" class="devsite-nav-title gc-analytics-event " data-category="Site-Wide Custom Events" data-label="Responsive Tab: Release & Monitor" track-type="navMenu" track-metadata-eventdetail="globalMenu" track-metadata-position="nav" track-name="release&Monitor"> <span class="devsite-nav-text" tooltip> Release & Monitor </span> </a> </li> <li class="devsite-nav-item"> <a href="/web/20210124195105/https://firebase.google.com/products-engage" class="devsite-nav-title gc-analytics-event " data-category="Site-Wide Custom Events" data-label="Responsive Tab: Engage" track-type="navMenu" track-metadata-eventdetail="globalMenu" track-metadata-position="nav" track-name="engage"> <span class="devsite-nav-text" tooltip> Engage </span> </a> </li> </ul> </div> </div> </nav> </devsite-book-nav> <section id="gc-wrapper"> <main role="main" class="devsite-main-content" has-book-nav has-toc> <devsite-toc class="devsite-nav"></devsite-toc> <devsite-content> <article class="devsite-article"><style> /* Styles inlined from /styles/docs.css */ .center { text-align: center } /* Used in AdMob code examples */ .oldcode { opacity: .40; /* IE 8 */ -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=40)"; filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=40); /* IE <= 7 */ filter:alpha(opacity=40); } .newcode { font-weight: bold; } /* Device Screenshots */ .deviceshot { max-width: 700px; max-height: 400px; } /* Start Changelog styles */ .badge { position: relative; top: -3px; border-radius: 16px; display: inline-block; 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.devsite-nav-icon::before, .devsite-nav-icon[data-icon="beta"]::before { content: url('data:image/svg+xml;base64,PHN2ZyB3aWR0aD0iMTgiIGhlaWdodD0iMTgiIHZpZXdCb3g9IjAgMCAxOCAxOCIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj48cGF0aCBkPSJNMTIuMjM2IDcuNjgzQTQgNCAwIDAgMSAxMCAxNUg3djJINVY0YTIgMiAwIDAgMSAyLTJoMi41YTMuNSAzLjUgMCAwIDEgMi43MzYgNS42ODN6TTcgMTNoM2EyIDIgMCAxIDAgMC00SDd2NHptMC02aDIuNWExLjUgMS41IDAgMCAwIDAtM0g3djN6IiBmaWxsPSJyZ2JhKDAsMCwwLC4zOCkiIGZpbGwtcnVsZT0ibm9uemVybyIvPjwvc3ZnPg=='); } .firebase-platform-label { font: 500 12px/24px Roboto,sans-serif; } /* Full-page platform selector dropdown */ /* Note: use menu variables in _elements.html file */ .full-page-selector-dropdown { border: none; position: relative; float: left; display: inline-block; } .full-page-selector-dropdown > .ds-selector-tabs { display: none; position: absolute; min-width: 160px; z-index: 1; } .full-page-selector-dropdown:hover .ds-selector-tabs { display: block; margin: 0; } .full-page-selector-dropdown:hover .kd-tabbutton { display: block; border: none; height: inherit; text-align: left; } .full-page-selector-dropdown:hover .kd-buttonbar { border: none; height: inherit; } .full-page-selector-dropdown h3:hover { color: white; background-color: #039be5; } .full-page-selector-dropdown:hover .devsite-overflow-menu-button { display: none; } </style> <div class="devsite-article-meta" role="navigation"> <ul class="devsite-breadcrumb-list" aria-label="Breadcrumb"> <li class="devsite-breadcrumb-item "> <a href="https://web.archive.org/web/20210124195105/https://firebase.google.com/" class="devsite-breadcrumb-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Breadcrumbs" data-value="1" track-type="globalNav" track-name="breadcrumb" track-metadata-position="1" track-metadata-eventdetail="Firebase"> Firebase </a> </li> <li class="devsite-breadcrumb-item "> <div class="devsite-breadcrumb-guillemet material-icons" aria-hidden="true"></div> <a href="https://web.archive.org/web/20210124195105/https://firebase.google.com/docs" class="devsite-breadcrumb-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Breadcrumbs" data-value="2" track-type="globalNav" track-name="breadcrumb" track-metadata-position="2" track-metadata-eventdetail=""> Docs </a> </li> <li class="devsite-breadcrumb-item "> <div class="devsite-breadcrumb-guillemet material-icons" aria-hidden="true"></div> <a href="https://web.archive.org/web/20210124195105/https://firebase.google.com/docs/database" class="devsite-breadcrumb-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Breadcrumbs" data-value="3" track-type="globalNav" track-name="breadcrumb" track-metadata-position="3" track-metadata-eventdetail="Firebase Realtime Database"> Firebase Realtime Database </a> </li> <li class="devsite-breadcrumb-item "> <div class="devsite-breadcrumb-guillemet material-icons" aria-hidden="true"></div> <a href="https://web.archive.org/web/20210124195105/https://firebase.google.com/docs/guides" class="devsite-breadcrumb-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Breadcrumbs" data-value="4" track-type="globalNav" track-name="breadcrumb" track-metadata-position="4" track-metadata-eventdetail=""> Guides </a> </li> </ul> <devsite-page-rating position="header" selected-rating="0" hover-rating-star="0"> </devsite-page-rating> </div> <devsite-feedback position="header" project-name="Firebase Realtime Database" product-id="719752" bucket="" context="" version="t-devsite-webserver-20210114-r02-rc00.432497685912973661" data-label="Send Feedback Button" track-type="feedback" track-name="sendFeedbackLink" track-metadata-position="header" project-feedback-url="https://firebase.google.com/support/contact/bugs-features/" project-icon="https://www.gstatic.com/devrel-devsite/prod/vbd4700e58d826f0eab371eadc20e0e343567df356800794a790eebf2ac059db2/firebase/images/touchicon-180.png" project-support-url="https://firebase.google.com/support/" feedback-type="star-rating"> <button> Send feedback </button> </devsite-feedback> <h1 class="devsite-page-title">Work with Lists of Data on Android</h1> <devsite-toc class="devsite-nav" devsite-toc-embedded> </devsite-toc> <div class="devsite-article-body clearfix "> <p>This document covers working with lists of data in Firebase. To learn the basics of reading and writing Firebase data see <a href="/web/20210124195105/https://firebase.google.com/docs/database/android/read-and-write">Read and Write Data on Android</a>.</p> <aside class="note"><strong>Note:</strong><span> By default, read and write access to your database is restricted so only authenticated users can read or write data. To get started without setting up <a href="/web/20210124195105/https://firebase.google.com/docs/auth">Authentication</a>, you can <a href="/web/20210124195105/https://firebase.google.com/docs/rules/basics#default_rules_locked_mode" target="_blank">configure your rules for public access</a>. This does make your database open to anyone, even people not using your app, so be sure to restrict your database again when you set up authentication.</span></aside> <h2 id="get_a_databasereference" data-text="Get a DatabaseReference">Get a DatabaseReference</h2> <p>To read and write data from the database, you need an instance of <code translate="no" dir="ltr">DatabaseReference</code>:</p> <div class="ds-selector-tabs"> <section> <h3 id="java" data-text="Java"><span class="two-line-tab"><span tab-label="Android">Java</span></span></h3> <pre class="prettyprint lang-java" translate="no" dir="ltr">private DatabaseReference mDatabase; // ... mDatabase = FirebaseDatabase.getInstance().getReference();<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/quickstart-android/blob/256c7e1e6e1dd2be7025bb3f858bf906fd158fa0/database/app/src/main/java/com/google/firebase/quickstart/database/java/NewPostActivity.java#L39-L39" class="gc-analytics-event" data-category="github_link" data-label="firebase/quickstart-android/database/app/src/main/java/com/google/firebase/quickstart/database/java/NewPostActivity.java#initialize_database_ref" data-code-snippet="true" data-github-path="firebase/quickstart-android/database/app/src/main/java/com/google/firebase/quickstart/database/java/NewPostActivity.java" data-region-tag="initialize_database_ref">NewPostActivity.java</a></div></pre> </section> <section> <h3 id="kotlin+ktx" data-text="Kotlin+KTX"><span class="two-line-tab"><span tab-label="Android">Kotlin+KTX</span></span></h3> <pre class="prettyprint lang-kotlin" translate="no" dir="ltr">private lateinit var database: DatabaseReference // ... database = Firebase.database.reference<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/quickstart-android/blob/256c7e1e6e1dd2be7025bb3f858bf906fd158fa0/database/app/src/main/java/com/google/firebase/quickstart/database/kotlin/NewPostActivity.kt#L31-L31" class="gc-analytics-event" data-category="github_link" data-label="firebase/quickstart-android/database/app/src/main/java/com/google/firebase/quickstart/database/kotlin/NewPostActivity.kt#initialize_database_ref" data-code-snippet="true" data-github-path="firebase/quickstart-android/database/app/src/main/java/com/google/firebase/quickstart/database/kotlin/NewPostActivity.kt" data-region-tag="initialize_database_ref">NewPostActivity.kt</a></div></pre> </section> </div> <h2 id="read_and_write_lists" data-text="Read and write lists">Read and write lists</h2> <h3 id="append_to_a_list_of_data" data-text="Append to a list of data">Append to a list of data</h3> <p>Use the <code translate="no" dir="ltr">push()</code> method to append data to a list in multiuser applications. The <code translate="no" dir="ltr">push()</code> method generates a unique key every time a new child is added to the specified Firebase reference. By using these auto-generated keys for each new element in the list, several clients can add children to the same location at the same time without write conflicts. The unique key generated by <code translate="no" dir="ltr">push()</code> is based on a timestamp, so list items are automatically ordered chronologically.</p> <p>You can use the reference to the new data returned by the <code translate="no" dir="ltr">push()</code> method to get the value of the child's auto-generated key or set data for the child. Calling <code translate="no" dir="ltr">getKey()</code> on a <code translate="no" dir="ltr">push()</code> reference returns the value of the auto-generated key.</p> <p>You can use these auto-generated keys to simplify flattening your data structure. For more information, see the data fan-out <a href="/web/20210124195105/https://firebase.google.com/docs/database/android/structure-data#fanout">example</a>.</p> <h3 id="child-events" data-text="Listen for child events">Listen for child events</h3> <p>When working with lists, your application should listen for child events rather than the value events used for single objects.</p> <p>Child events are triggered in response to specific operations that happen to the children of a node from an operation such as a new child added through the <code translate="no" dir="ltr">push()</code> method or a child being updated through the <code translate="no" dir="ltr">updateChildren()</code> method. Each of these together can be useful for listening to changes to a specific node in a database.</p> <p>In order to listen for child events on <code translate="no" dir="ltr">DatabaseReference</code>, attach a <code translate="no" dir="ltr">ChildEventListener</code>:</p> <table> <tr> <th>Listener</th> <th>Event callback</th> <th>Typical usage</th> </tr> <tr> <td rowspan="4"><code translate="no" dir="ltr">ChildEventListener</code> <td><code translate="no" dir="ltr">onChildAdded()</code></td> <td> Retrieve lists of items or listen for additions to a list of items. This callback is triggered once for each existing child and then again every time a new child is added to the specified path. The <code translate="no" dir="ltr">DataSnapshot</code> passed to the listener contains the the new child's data. </td> </tr> <tr> <td><code translate="no" dir="ltr">onChildChanged()</code></td> <td> Listen for changes to the items in a list. This event fired any time a child node is modified, including any modifications to descendants of the child node. The <code translate="no" dir="ltr">DataSnapshot</code> passed to the event listener contains the updated data for the child. </td> </tr> <tr> <td><code translate="no" dir="ltr">onChildRemoved()</code></td> <td> Listen for items being removed from a list. The <code translate="no" dir="ltr">DataSnapshot</code> passed to the event callback contains the data for the removed child. </td> </tr> <tr> <td><code translate="no" dir="ltr">onChildMoved()</code></td> <td> Listen for changes to the order of items in an ordered list. This event is triggered whenever the <code translate="no" dir="ltr">onChildChanged()</code> callback is triggered by an update that causes reordering of the child. It is used with data that is ordered with <code translate="no" dir="ltr">orderByChild</code> or <code translate="no" dir="ltr">orderByValue</code>. </td> </tr> </table> <p>For example, a social blogging app might use these methods together to monitor activity in the comments of a post, as shown below:</p> <div class="ds-selector-tabs" data-ds-scope="code-sample"> <section><h3 id="java_1" data-text=" Java "> <span class="two-line-tab"><span tab-label="Android">Java</span></span> </h3><pre class="prettyprint lang-java" translate="no" dir="ltr" data-code-snippet="true" data-github-path="firebase/quickstart-android/database/app/src/main/java/com/google/firebase/quickstart/database/java/PostDetailActivity.java" data-region-tag="child_event_listener_recycler">ChildEventListener childEventListener = new ChildEventListener() { @Override public void onChildAdded(DataSnapshot dataSnapshot, String previousChildName) { Log.d(TAG, "onChildAdded:" + dataSnapshot.getKey()); // A new comment has been added, add it to the displayed list Comment comment = dataSnapshot.getValue(Comment.class); // ... } @Override public void onChildChanged(DataSnapshot dataSnapshot, String previousChildName) { Log.d(TAG, "onChildChanged:" + dataSnapshot.getKey()); // A comment has changed, use the key to determine if we are displaying this // comment and if so displayed the changed comment. Comment newComment = dataSnapshot.getValue(Comment.class); String commentKey = dataSnapshot.getKey(); // ... } @Override public void onChildRemoved(DataSnapshot dataSnapshot) { Log.d(TAG, "onChildRemoved:" + dataSnapshot.getKey()); // A comment has changed, use the key to determine if we are displaying this // comment and if so remove it. String commentKey = dataSnapshot.getKey(); // ... } @Override public void onChildMoved(DataSnapshot dataSnapshot, String previousChildName) { Log.d(TAG, "onChildMoved:" + dataSnapshot.getKey()); // A comment has changed position, use the key to determine if we are // displaying this comment and if so move it. Comment movedComment = dataSnapshot.getValue(Comment.class); String commentKey = dataSnapshot.getKey(); // ... } @Override public void onCancelled(DatabaseError databaseError) { Log.w(TAG, "postComments:onCancelled", databaseError.toException()); Toast.makeText(mContext, "Failed to load comments.", Toast.LENGTH_SHORT).show(); } }; ref.addChildEventListener(childEventListener);<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/quickstart-android/blob/256c7e1e6e1dd2be7025bb3f858bf906fd158fa0/database/app/src/main/java/com/google/firebase/quickstart/database/java/PostDetailActivity.java#L181-L262" class="gc-analytics-event" data-category="github_link" data-label="firebase/quickstart-android/database/app/src/main/java/com/google/firebase/quickstart/database/java/PostDetailActivity.java#child_event_listener_recycler">PostDetailActivity.java</a></div></pre></section> <section><h3 id="kotlin+ktx_1" data-text=" Kotlin+KTX "> <span class="two-line-tab"><span tab-label="Android">Kotlin+KTX</span></span> </h3><pre class="prettyprint lang-kotlin" translate="no" dir="ltr" data-code-snippet="true" data-github-path="firebase/quickstart-android/database/app/src/main/java/com/google/firebase/quickstart/database/kotlin/PostDetailActivity.kt" data-region-tag="child_event_listener_recycler">val childEventListener = object : ChildEventListener { override fun onChildAdded(dataSnapshot: DataSnapshot, previousChildName: String?) { Log.d(TAG, "onChildAdded:" + dataSnapshot.key!!) // A new comment has been added, add it to the displayed list val comment = dataSnapshot.getValue<Comment>() // ... } override fun onChildChanged(dataSnapshot: DataSnapshot, previousChildName: String?) { Log.d(TAG, "onChildChanged: ${dataSnapshot.key}") // A comment has changed, use the key to determine if we are displaying this // comment and if so displayed the changed comment. val newComment = dataSnapshot.getValue<Comment>() val commentKey = dataSnapshot.key // ... } override fun onChildRemoved(dataSnapshot: DataSnapshot) { Log.d(TAG, "onChildRemoved:" + dataSnapshot.key!!) // A comment has changed, use the key to determine if we are displaying this // comment and if so remove it. val commentKey = dataSnapshot.key // ... } override fun onChildMoved(dataSnapshot: DataSnapshot, previousChildName: String?) { Log.d(TAG, "onChildMoved:" + dataSnapshot.key!!) // A comment has changed position, use the key to determine if we are // displaying this comment and if so move it. val movedComment = dataSnapshot.getValue<Comment>() val commentKey = dataSnapshot.key // ... } override fun onCancelled(databaseError: DatabaseError) { Log.w(TAG, "postComments:onCancelled", databaseError.toException()) Toast.makeText(context, "Failed to load comments.", Toast.LENGTH_SHORT).show() } } databaseReference.addChildEventListener(childEventListener)<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/quickstart-android/blob/256c7e1e6e1dd2be7025bb3f858bf906fd158fa0/database/app/src/main/java/com/google/firebase/quickstart/database/kotlin/PostDetailActivity.kt#L171-L247" class="gc-analytics-event" data-category="github_link" data-label="firebase/quickstart-android/database/app/src/main/java/com/google/firebase/quickstart/database/kotlin/PostDetailActivity.kt#child_event_listener_recycler">PostDetailActivity.kt</a></div></pre></section> </div> <h3 id="listen_for_value_events" data-text="Listen for value events">Listen for value events</h3> <p>While using a <code translate="no" dir="ltr">ChildEventListener</code> is the recommended way to read lists of data, there are situations where attaching a <code translate="no" dir="ltr">ValueEventListener</code> to a list reference is useful.</p> <p>Attaching a <code translate="no" dir="ltr">ValueEventListener</code> to a list of data will return the entire list of data as a single <code translate="no" dir="ltr">DataSnapshot</code>, which you can then loop over to access individual children.</p> <p>Even when there is only a single match for the query, the snapshot is still a list; it just contains a single item. To access the item, you need to loop over the result:</p> <div class="ds-selector-tabs" data-ds-scope="code-sample"> <section><h3 id="java_2" data-text=" Java "> <span class="two-line-tab"><span tab-label="Android">Java</span></span> </h3><pre class="prettyprint lang-java" translate="no" dir="ltr" data-code-snippet="true" data-github-path="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/QueryActivity.java" data-region-tag="basic_query_value_listener">// My top posts by number of stars myTopPostsQuery.addValueEventListener(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) { // TODO: handle the post } } @Override public void onCancelled(DatabaseError databaseError) { // Getting Post failed, log a message Log.w(TAG, "loadPost:onCancelled", databaseError.toException()); // ... } });<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/snippets-android/blob/3cdf635260fbc295cfd4649df1bbf23bea8f5d7c/database/app/src/main/java/com/google/firebase/referencecode/database/QueryActivity.java#L122-L137" class="gc-analytics-event" data-category="github_link" data-label="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/QueryActivity.java#basic_query_value_listener">QueryActivity.java</a></div></pre></section> <section><h3 id="kotlin+ktx_2" data-text=" Kotlin+KTX "> <span class="two-line-tab"><span tab-label="Android">Kotlin+KTX</span></span> </h3><pre class="prettyprint lang-kotlin" translate="no" dir="ltr" data-code-snippet="true" data-github-path="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/kotlin/QueryActivity.kt" data-region-tag="basic_query_value_listener">// My top posts by number of stars myTopPostsQuery.addValueEventListener(object : ValueEventListener { override fun onDataChange(dataSnapshot: DataSnapshot) { for (postSnapshot in dataSnapshot.children) { // TODO: handle the post } } override fun onCancelled(databaseError: DatabaseError) { // Getting Post failed, log a message Log.w(TAG, "loadPost:onCancelled", databaseError.toException()) // ... } })<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/snippets-android/blob/3cdf635260fbc295cfd4649df1bbf23bea8f5d7c/database/app/src/main/java/com/google/firebase/referencecode/database/kotlin/QueryActivity.kt#L102-L115" class="gc-analytics-event" data-category="github_link" data-label="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/kotlin/QueryActivity.kt#basic_query_value_listener">QueryActivity.kt</a></div></pre></section> </div> <p>This pattern can be useful when you want to fetch all children of a list in a single operation, rather than listening for additional <code translate="no" dir="ltr">onChildAdded</code> events.</p> <h2 id="detach_listeners" data-text="Detach listeners">Detach listeners</h2> <p>Callbacks are removed by calling the <code translate="no" dir="ltr">removeEventListener()</code> method on your Firebase database reference.</p> <p>If a listener has been added multiple times to a data location, it is called multiple times for each event, and you must detach it the same number of times to remove it completely.</p> <p>Calling <code translate="no" dir="ltr">removeEventListener()</code> on a parent listener does not automatically remove listeners registered on its child nodes; <code translate="no" dir="ltr">removeEventListener()</code> must also be called on any child listeners to remove the callback.</p> <h2 id="sorting_and_filtering_data" data-text="Sorting and filtering data">Sorting and filtering data</h2> <p>You can use the Realtime Database <code translate="no" dir="ltr">Query</code> class to retrieve data sorted by key, by value, or by value of a child. You can also filter the sorted result to a specific number of results or a range of keys or values.</p> <aside class="note"><strong>Note:</strong><span> Filtering and sorting can be expensive, especially when done on the client. If your app uses queries, define the <code translate="no" dir="ltr">.indexOn</code> rule to index those keys on the server and improve query performance as described in <a href="/web/20210124195105/https://firebase.google.com/docs/database/security/indexing-data">Indexing Your Data</a>.</span></aside> <h3 id="sort_data" data-text="Sort data">Sort data</h3> <p>To retrieve sorted data, start by specifying one of the order-by methods to determine how results are ordered:</p> <table> <tr> <th>Method</th> <th>Usage</th> </tr> <tr> <td><code translate="no" dir="ltr">orderByChild()</code></td> <td>Order results by the value of a specified child key or nested child path.</td> </tr> <td><code translate="no" dir="ltr">orderByKey()</code> <td>Order results by child keys.</td> <tr> <td><code translate="no" dir="ltr">orderByValue()</code></td> <td>Order results by child values.</td> </tr> </table> <p>You can only use <strong>one</strong> order-by method at a time. Calling an order-by method multiple times in the same query throws an error.</p> <p>The following example demonstrates how you could retrieve a list of a user's top posts sorted by their star count:</p> <div class="ds-selector-tabs" data-ds-scope="code-sample"> <section><h3 id="java_3" data-text=" Java "> <span class="two-line-tab"><span tab-label="Android">Java</span></span> </h3><pre class="prettyprint lang-java" translate="no" dir="ltr" data-code-snippet="true" data-github-path="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/QueryActivity.java" data-region-tag="basic_query">// My top posts by number of stars String myUserId = getUid(); Query myTopPostsQuery = databaseReference.child("user-posts").child(myUserId) .orderByChild("starCount"); myTopPostsQuery.addChildEventListener(new ChildEventListener() { // TODO: implement the ChildEventListener methods as documented above // ... });<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/snippets-android/blob/3cdf635260fbc295cfd4649df1bbf23bea8f5d7c/database/app/src/main/java/com/google/firebase/referencecode/database/QueryActivity.java#L99-L112" class="gc-analytics-event" data-category="github_link" data-label="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/QueryActivity.java#basic_query">QueryActivity.java</a></div></pre></section> <section><h3 id="kotlin+ktx_3" data-text=" Kotlin+KTX "> <span class="two-line-tab"><span tab-label="Android">Kotlin+KTX</span></span> </h3><pre class="prettyprint lang-kotlin" translate="no" dir="ltr" data-code-snippet="true" data-github-path="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/kotlin/QueryActivity.kt" data-region-tag="basic_query">// My top posts by number of stars val myUserId = uid val myTopPostsQuery = databaseReference.child("user-posts").child(myUserId) .orderByChild("starCount") myTopPostsQuery.addChildEventListener(object : ChildEventListener { // TODO: implement the ChildEventListener methods as documented above // ... })<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/snippets-android/blob/3cdf635260fbc295cfd4649df1bbf23bea8f5d7c/database/app/src/main/java/com/google/firebase/referencecode/database/kotlin/QueryActivity.kt#L77-L92" class="gc-analytics-event" data-category="github_link" data-label="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/kotlin/QueryActivity.kt#basic_query">QueryActivity.kt</a></div></pre></section> </div> <p>This defines a query that when combined with a <a href="#child-events">child listener</a> synchronizes the client with the user's posts from the path in the database based on their user ID, ordered by the number of stars each post has received. This technique of using IDs as index keys is called data fan out, you can read more about it in <a href="/web/20210124195105/https://firebase.google.com/docs/database/android/structure-data#fanout">Structure Your Database</a>.</p> <p>The call to the <code translate="no" dir="ltr">orderByChild()</code> method specifies the child key to order the results by. In this case, posts are sorted by the value of their respective <code translate="no" dir="ltr">"starCount"</code> child. Queries can also be ordered by nested children, in case you have data that looks like this:</p> <pre class="prettyprint" translate="no" dir="ltr"> "posts": { "ts-functions": { "metrics": { "views" : 1200000, "likes" : 251000, "shares": 1200, }, "title" : "Why you should use TypeScript for writing Cloud Functions", "author": "Doug", }, "android-arch-3": { "metrics": { "views" : 900000, "likes" : 117000, "shares": 144, }, "title" : "Using Android Architecture Components with Firebase Realtime Database (Part 3)", "author": "Doug", } }, </pre> <p>In this example, we can order our list elements by values nested under the <code translate="no" dir="ltr">metrics</code> key by specifying the relative path to the nested child in our <code translate="no" dir="ltr">orderByChild()</code> call.</p> <div class="ds-selector-tabs" data-ds-scope="code-sample"> <section><h3 id="java_4" data-text=" Java "> <span class="two-line-tab"><span tab-label="Android">Java</span></span> </h3><pre class="prettyprint lang-java" translate="no" dir="ltr" data-code-snippet="true" data-github-path="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/QueryActivity.java" data-region-tag="rtdb_order_by_nested">// Most viewed posts Query myMostViewedPostsQuery = databaseReference.child("posts") .orderByChild("metrics/views"); myMostViewedPostsQuery.addChildEventListener(new ChildEventListener() { // TODO: implement the ChildEventListener methods as documented above // ... });<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/snippets-android/blob/3cdf635260fbc295cfd4649df1bbf23bea8f5d7c/database/app/src/main/java/com/google/firebase/referencecode/database/QueryActivity.java#L157-L178" class="gc-analytics-event" data-category="github_link" data-label="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/QueryActivity.java#rtdb_order_by_nested">QueryActivity.java</a></div></pre></section> <section><h3 id="kotlin+ktx_4" data-text=" Kotlin+KTX "> <span class="two-line-tab"><span tab-label="Android">Kotlin+KTX</span></span> </h3><pre class="prettyprint lang-kotlin" translate="no" dir="ltr" data-code-snippet="true" data-github-path="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/kotlin/QueryActivity.kt" data-region-tag="rtdb_order_by_nested">// Most viewed posts val myMostViewedPostsQuery = databaseReference.child("posts") .orderByChild("metrics/views") myMostViewedPostsQuery.addChildEventListener(object : ChildEventListener { // TODO: implement the ChildEventListener methods as documented above // ... })<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/snippets-android/blob/3cdf635260fbc295cfd4649df1bbf23bea8f5d7c/database/app/src/main/java/com/google/firebase/referencecode/database/kotlin/QueryActivity.kt#L135-L151" class="gc-analytics-event" data-category="github_link" data-label="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/kotlin/QueryActivity.kt#rtdb_order_by_nested">QueryActivity.kt</a></div></pre></section> </div> <p>For more information on how other data types are ordered, see <a href="#data-order">How query data is ordered</a>.</p> <h3 id="filtering_data" data-text="Filtering data">Filtering data</h3> <p>To filter data, you can combine any of the limit or range methods with an order-by method when constructing a query.</p> <table> <tr> <th>Method</th> <th>Usage</th> </tr> <tr> <td><code translate="no" dir="ltr">limitToFirst()</code></td> <td>Sets the maximum number of items to return from the beginning of the ordered list of results.</td> </tr> <tr> <td><code translate="no" dir="ltr">limitToLast()</code></td> <td>Sets the maximum number of items to return from the end of the ordered list of results. </tr> <tr> <td><code translate="no" dir="ltr">startAt()</code></td> <td>Return items greater than or equal to the specified key or value depending on the order-by method chosen.</td> </tr> <tr> <td><code translate="no" dir="ltr">endAt()</code></td> <td>Return items less than or equal to the specified key or value depending on the order-by method chosen.</td> </tr> <tr> <td><code translate="no" dir="ltr">equalTo()</code></td> <td>Return items equal to the specified key or value depending on the order-by method chosen.</td> </tr> </table> <p>Unlike the order-by methods, you can combine multiple limit or range functions. For example, you can combine the <code translate="no" dir="ltr">startAt()</code> and <code translate="no" dir="ltr">endAt()</code> methods to limit the results to a specified range of values.</p> <p>Even when there is only a single match for the query, the snapshot is still a list; it just contains a single item. To access the item, you need to loop over the result:</p> <div class="ds-selector-tabs" data-ds-scope="code-sample"> <section><h3 id="java_5" data-text=" Java "> <span class="two-line-tab"><span tab-label="Android">Java</span></span> </h3><pre class="prettyprint lang-java" translate="no" dir="ltr" data-code-snippet="true" data-github-path="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/QueryActivity.java" data-region-tag="basic_query_value_listener">// My top posts by number of stars myTopPostsQuery.addValueEventListener(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) { // TODO: handle the post } } @Override public void onCancelled(DatabaseError databaseError) { // Getting Post failed, log a message Log.w(TAG, "loadPost:onCancelled", databaseError.toException()); // ... } });<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/snippets-android/blob/3cdf635260fbc295cfd4649df1bbf23bea8f5d7c/database/app/src/main/java/com/google/firebase/referencecode/database/QueryActivity.java#L122-L137" class="gc-analytics-event" data-category="github_link" data-label="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/QueryActivity.java#basic_query_value_listener">QueryActivity.java</a></div></pre></section> <section><h3 id="kotlin+ktx_5" data-text=" Kotlin+KTX "> <span class="two-line-tab"><span tab-label="Android">Kotlin+KTX</span></span> </h3><pre class="prettyprint lang-kotlin" translate="no" dir="ltr" data-code-snippet="true" data-github-path="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/kotlin/QueryActivity.kt" data-region-tag="basic_query_value_listener">// My top posts by number of stars myTopPostsQuery.addValueEventListener(object : ValueEventListener { override fun onDataChange(dataSnapshot: DataSnapshot) { for (postSnapshot in dataSnapshot.children) { // TODO: handle the post } } override fun onCancelled(databaseError: DatabaseError) { // Getting Post failed, log a message Log.w(TAG, "loadPost:onCancelled", databaseError.toException()) // ... } })<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/snippets-android/blob/3cdf635260fbc295cfd4649df1bbf23bea8f5d7c/database/app/src/main/java/com/google/firebase/referencecode/database/kotlin/QueryActivity.kt#L102-L115" class="gc-analytics-event" data-category="github_link" data-label="firebase/snippets-android/database/app/src/main/java/com/google/firebase/referencecode/database/kotlin/QueryActivity.kt#basic_query_value_listener">QueryActivity.kt</a></div></pre></section> </div> <h4 id="limit_the_number_of_results" data-text="Limit the number of results">Limit the number of results</h4> <p>You can use the <code translate="no" dir="ltr">limitToFirst()</code> and <code translate="no" dir="ltr">limitToLast()</code> methods to set a maximum number of children to be synced for a given callback. For example, if you use <code translate="no" dir="ltr">limitToFirst()</code> to set a limit of 100, you initially only receive up to 100 <code translate="no" dir="ltr">onChildAdded()</code> callbacks. If you have fewer than 100 items stored in your Firebase database, an <code translate="no" dir="ltr">onChildAdded()</code> callback fires for each item.</p> <p>As items change, you receive <code translate="no" dir="ltr">onChildAdded()</code> callbacks for items that enter the query and <code translate="no" dir="ltr">onChildRemoved()</code> callbacks for items that drop out of it so that the total number stays at 100.</p> <p>The following example demonstrates how example blogging app defines a query to retrieve a list of the 100 most recent posts by all users:</p> <div class="ds-selector-tabs" data-ds-scope="code-sample"> <section><h3 id="java_6" data-text=" Java "> <span class="two-line-tab"><span tab-label="Android">Java</span></span> </h3><pre class="prettyprint lang-java" translate="no" dir="ltr" data-code-snippet="true" data-github-path="firebase/quickstart-android/database/app/src/main/java/com/google/firebase/quickstart/database/java/fragment/RecentPostsFragment.java" data-region-tag="recent_posts_query">// Last 100 posts, these are automatically the 100 most recent // due to sorting by push() keys Query recentPostsQuery = databaseReference.child("posts") .limitToFirst(100);<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/quickstart-android/blob/256c7e1e6e1dd2be7025bb3f858bf906fd158fa0/database/app/src/main/java/com/google/firebase/quickstart/database/java/fragment/RecentPostsFragment.java#L13-L16" class="gc-analytics-event" data-category="github_link" data-label="firebase/quickstart-android/database/app/src/main/java/com/google/firebase/quickstart/database/java/fragment/RecentPostsFragment.java#recent_posts_query">RecentPostsFragment.java</a></div></pre></section> <section><h3 id="kotlin+ktx_6" data-text=" Kotlin+KTX "> <span class="two-line-tab"><span tab-label="Android">Kotlin+KTX</span></span> </h3><pre class="prettyprint lang-kotlin" translate="no" dir="ltr" data-code-snippet="true" data-github-path="firebase/quickstart-android/database/app/src/main/java/com/google/firebase/quickstart/database/kotlin/fragment/RecentPostsFragment.kt" data-region-tag="recent_posts_query">// Last 100 posts, these are automatically the 100 most recent // due to sorting by push() keys. return databaseReference.child("posts") .limitToFirst(100)<div class="devsite-github-link nocode no-select"><a target="_top" href="https://web.archive.org/web/20210124195105/https://github.com/firebase/quickstart-android/blob/256c7e1e6e1dd2be7025bb3f858bf906fd158fa0/database/app/src/main/java/com/google/firebase/quickstart/database/kotlin/fragment/RecentPostsFragment.kt#L10-L13" class="gc-analytics-event" data-category="github_link" data-label="firebase/quickstart-android/database/app/src/main/java/com/google/firebase/quickstart/database/kotlin/fragment/RecentPostsFragment.kt#recent_posts_query">RecentPostsFragment.kt</a></div></pre></section> </div> <p>This example only defines a query, to actually synchronize data it needs to have an attached <a href="#child-events">listener</a>.</p> <h4 id="filter_by_key_or_value" data-text="Filter by key or value">Filter by key or value</h4> <p>You can use <code translate="no" dir="ltr">startAt()</code>, <code translate="no" dir="ltr">endAt()</code>, and <code translate="no" dir="ltr">equalTo()</code> to choose arbitrary starting, ending, and equivalence points for queries. This can be useful for paginating data or finding items with children that have a specific value.</p> <h3 id="data-order" data-text="How query data is ordered">How query data is ordered</h3> <p>This section explains how data is sorted by each of the order-by methods in the <code translate="no" dir="ltr">Query</code> class.</p> <h4 id="orderbychild" data-text="orderByChild"><code translate="no" dir="ltr">orderByChild</code></h4> <p>When using <code translate="no" dir="ltr">orderByChild()</code>, data that contains the specified child key is ordered as follows:</p> <ol> <li>Children with a <code translate="no" dir="ltr">null</code> value for the specified child key come first.</li> <li>Children with a value of <code translate="no" dir="ltr">false</code> for the specified child key come next. If multiple children have a value of <code translate="no" dir="ltr">false</code>, they are sorted <a href="https://web.archive.org/web/20210124195105/http://en.wikipedia.org/wiki/Lexicographical_order">lexicographically</a> by key.</li> <li>Children with a value of <code translate="no" dir="ltr">true</code> for the specified child key come next. If multiple children have a value of <code translate="no" dir="ltr">true</code>, they are sorted lexicographically by key.</li> <li>Children with a numeric value come next, sorted in ascending order. If multiple children have the same numerical value for the specified child node, they are sorted by key.</li> <li>Strings come after numbers and are sorted lexicographically in ascending order. If multiple children have the same value for the specified child node, they are ordered lexicographically by key.</li> <li>Objects come last and are sorted lexicographically by key in ascending order.</li> </ol> <h4 id="orderbykey" data-text="orderByKey"><code translate="no" dir="ltr">orderByKey</code></h4> <p>When using <code translate="no" dir="ltr">orderByKey()</code> to sort your data, data is returned in ascending order by key.</p> <ol> <li>Children with a key that can be parsed as a 32-bit integer come first, sorted in ascending order.</li> <li>Children with a string value as their key come next, sorted lexicographically in ascending order.</li> </ol> <h4 id="orderbyvalue" data-text="orderByValue"><code translate="no" dir="ltr">orderByValue</code></h4> <p>When using <code translate="no" dir="ltr">orderByValue()</code>, children are ordered by their value. The ordering criteria are the same as in <code translate="no" dir="ltr">orderByChild()</code>, except the value of the node is used instead of the value of a specified child key.</p> <h2 id="next_steps" data-text="Next steps">Next steps</h2> <ul> <li><a href="/web/20210124195105/https://firebase.google.com/docs/database/android/structure-data">Learn how to structure data</a></li> <li><a href="/web/20210124195105/https://firebase.google.com/docs/database/android/offline-capabilities">Store data offline</a></li> </ul> </div> <devsite-page-rating position="footer" selected-rating="0" hover-rating-star="0"> </devsite-page-rating> <devsite-feedback position="footer" project-name="Firebase Realtime Database" product-id="719752" bucket="" context="" version="t-devsite-webserver-20210114-r02-rc00.432497685912973661" data-label="Send Feedback Button" track-type="feedback" track-name="sendFeedbackLink" track-metadata-position="footer" project-feedback-url="https://firebase.google.com/support/contact/bugs-features/" project-icon="https://www.gstatic.com/devrel-devsite/prod/vbd4700e58d826f0eab371eadc20e0e343567df356800794a790eebf2ac059db2/firebase/images/touchicon-180.png" project-support-url="https://firebase.google.com/support/" feedback-type="star-rating"> <button> Send feedback </button> </devsite-feedback> </article> <devsite-content-footer class="nocontent"> <p>Except as otherwise noted, the content of this page is licensed under the <a href="https://web.archive.org/web/20210124195105/https://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution 4.0 License</a>, and code samples are licensed under the <a href="https://web.archive.org/web/20210124195105/https://www.apache.org/licenses/LICENSE-2.0">Apache 2.0 License</a>. 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