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alt="Docusaurus themed image" class="themedComponent_mlkZ themedComponent--dark_xIcU" style="height:18px;width:18px;margin-right:6px">statsig-io/node-js-server-sdk</a></div><div style="height:4px"></div> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="installation">Installation<a href="#installation" class="hash-link" aria-label="Direct link to Installation" title="Direct link to Installation"></a></h2> <div><div class="theme-admonition theme-admonition-info admonition_xJq3 alert alert--info"><div class="admonitionHeading_Gvgb"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M7 2.3c3.14 0 5.7 2.56 5.7 5.7s-2.56 5.7-5.7 5.7A5.71 5.71 0 0 1 1.3 8c0-3.14 2.56-5.7 5.7-5.7zM7 1C3.14 1 0 4.14 0 8s3.14 7 7 7 7-3.14 7-7-3.14-7-7-7zm1 3H6v5h2V4zm0 6H6v2h2v-2z"></path></svg>info</div><div class="admonitionContent_BuS1">This doc reflect v6.x.x changes, upgrade guide to be found <a href="/server/nodejsServerSDK/upgrade_guide/v5ToV6">here</a></div></div> <div class="theme-admonition theme-admonition-warning admonition_xJq3 alert alert--warning"><div class="admonitionHeading_Gvgb"><svg viewBox="0 0 16 16"><path fill-rule="evenodd" d="M8.893 1.5c-.183-.31-.52-.5-.887-.5s-.703.19-.886.5L.138 13.499a.98.98 0 0 0 0 1.001c.193.31.53.501.886.501h13.964c.367 0 .704-.19.877-.5a1.03 1.03 0 0 0 .01-1.002L8.893 1.5zm.133 11.497H6.987v-2.003h2.039v2.003zm0-3.004H6.987V5.987h2.039v4.006z"></path></svg>warning</div><div class="admonitionContent_BuS1">If you are using node with one of the <a href="https://docs.statsig.com/guides/serverless" target="_blank" rel="noopener noreferrer">edge</a> integration, please still use version <code><=v5.x.x</code></div></div> The Node.js SDK is hosted <a href="https://www.npmjs.com/package/statsig-node" target="_blank" rel="noopener noreferrer">here</a>. You can install the SDK using NPM or Yarn: <div class="tabs-container tabList__CuJ"><ul role="tablist" aria-orientation="horizontal" class="tabs"><li role="tab" tabindex="0" aria-selected="true" class="tabs__item tabItem_LNqP tabs__item--active">NPM</li><li role="tab" tabindex="-1" aria-selected="false" class="tabs__item tabItem_LNqP">Yarn</li></ul><div class="margin-top--md"><div role="tabpanel" class="tabItem_Ymn6"><div class="language-shell codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-shell codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">npm install statsig-node </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div><div role="tabpanel" class="tabItem_Ymn6" hidden=""><div class="language-shell codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-shell codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">yarn add statsig-node </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div></div></div></div> <div style="height:4px"></div> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="initialize-the-sdk">Initialize the SDK<a href="#initialize-the-sdk" class="hash-link" aria-label="Direct link to Initialize the SDK" title="Direct link to Initialize the SDK"></a></h2> After installation, you will need to initialize the SDK using a <a href="https://console.statsig.com/api_keys" target="_blank" rel="noopener noreferrer">Server Secret Key from the statsig console</a>. <div class="theme-admonition theme-admonition-info admonition_xJq3 alert alert--info"><div class="admonitionHeading_Gvgb"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M7 2.3c3.14 0 5.7 2.56 5.7 5.7s-2.56 5.7-5.7 5.7A5.71 5.71 0 0 1 1.3 8c0-3.14 2.56-5.7 5.7-5.7zM7 1C3.14 1 0 4.14 0 8s3.14 7 7 7 7-3.14 7-7-3.14-7-7-7zm1 3H6v5h2V4zm0 6H6v2h2v-2z"></path></svg>info</div><div class="admonitionContent_BuS1">Do NOT embed your Server Secret Key in client-side applications, or expose it in any external-facing documents. However, if you accidentally expose it, you can create a new one in the Statsig console.</div></div> <div>There is also an optional parameter named <code>options</code> that allows you to pass in a <a href="#statsig-options">StatsigOptions</a> to customize the SDK.</div> <div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">const Statsig = require("statsig-node"); await Statsig.initialize( "server-secret-key", { environment: { tier: "staging" } } // optional, if not set, for >v6.0.0, sdk will default to be production ); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div> <div><code>initialize</code> will perform a network request. After <code>initialize</code> completes, virtually all SDK operations will be synchronous (See <a href="https://blog.statsig.com/evaluating-feature-gates-in-the-statsig-sdk-a6f8881a1ad8" target="_blank" rel="noopener noreferrer">Evaluating Feature Gates in the Statsig SDK</a>). The SDK will fetch updates from Statsig in the background, independently of your API calls.</div> <div style="height:4px"></div><div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="working-with-the-sdk">Working with the SDK<a href="#working-with-the-sdk" class="hash-link" aria-label="Direct link to Working with the SDK" title="Direct link to Working with the SDK"></a></h2> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="checking-a-feature-flaggate">Checking a Feature Flag/Gate<a href="#checking-a-feature-flaggate" class="hash-link" aria-label="Direct link to Checking a Feature Flag/Gate" title="Direct link to Checking a Feature Flag/Gate"></a></h3> Now that your SDK is initialized, let's fetch a <a href="/feature-flags/working-with">Feature Gate</a>. Feature Gates can be used to create logic branches in code that can be rolled out to different users from the Statsig Console. Gates are always CLOSED or OFF (think <code>return false;</code>) by default. From this point on, all APIs will require you to specify the user (see <a href="#statsig-user">Statsig user</a>) associated with the request. For example, check a gate for a certain user like this: <div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">const user = { userID: '12345', email: '12345@gmail.com', ... }; const showNewDesign = Statsig.checkGate(user, 'new_homepage_design'); if (showNewDesign) { // show new design here } else { // show old design here } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="reading-a-dynamic-config">Reading a Dynamic Config<a href="#reading-a-dynamic-config" class="hash-link" aria-label="Direct link to Reading a Dynamic Config" title="Direct link to Reading a Dynamic Config"></a></h3> Feature Gates can be very useful for simple on/off switches, with optional but advanced user targeting. However, if you want to be able send a different set of values (strings, numbers, and etc.) to your clients based on specific user attributes, e.g. country, <a href="/dynamic-config">Dynamic Configs</a> can help you with that. The API is very similar to Feature Gates, but you get an entire json object you can configure on the server and you can fetch typed parameters from it. For example: <div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">const config = Statsig.getConfig(user, "awesome_product_details"); // The 2nd parameter is the default value to be used in case the given parameter name does not exist on // the Dynamic Config object. This can happen when there is a typo, or when the user is offline and the // value has not been cached on the client. const itemName = config.get("product_name", "Awesome Product v1"); const price = config.get("price", 10.0); const shouldDiscount = config.get("discount", false); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="getting-an-layerexperiment">Getting an Layer/Experiment<a href="#getting-an-layerexperiment" class="hash-link" aria-label="Direct link to Getting an Layer/Experiment" title="Direct link to Getting an Layer/Experiment"></a></h3> Then we have Layers/Experiments, which you can use to run A/B/n experiments. We offer two APIs, but we recommend the use of <a href="/layers">layers</a> to enable quicker iterations with parameter reuse. <div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">// Values via getLayer const layer = Statsig.getLayer(user, "user_promo_experiments"); const promoTitle = layer.get("title", "Welcome to Statsig!"); const discount = layer.get("discount", 0.1); // or, via getExperiment const promoExperiment = Statsig.getExperiment(user, "new_user_promo"); const promoTitle = promoExperiment.get("title", "Welcome to Statsig!"); const discount = promoExperiment.get("discount", 0.1); ... const price = msrp * (1 - discount); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div> <div class="theme-admonition theme-admonition-info admonition_xJq3 alert alert--info"><div class="admonitionHeading_Gvgb"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M7 2.3c3.14 0 5.7 2.56 5.7 5.7s-2.56 5.7-5.7 5.7A5.71 5.71 0 0 1 1.3 8c0-3.14 2.56-5.7 5.7-5.7zM7 1C3.14 1 0 4.14 0 8s3.14 7 7 7 7-3.14 7-7-3.14-7-7-7zm1 3H6v5h2V4zm0 6H6v2h2v-2z"></path></svg>Asynchronous APIs</div><div class="admonitionContent_BuS1">We mentioned earlier that after calling <code>initialize</code> most SDK APIs would run synchronously, so why are <code>getConfig</code> and <code>checkGate</code> asynchronous?The main reason is that older versions of the SDK might not know how to interpret new types of gate conditions. In such cases the SDK will make an asynchronous call to our servers to fetch the result of a check. This can be resolved by upgrading the SDK, and we will warn you if this happens.For more details, read our <a href="https://blog.statsig.com/evaluating-feature-gates-in-the-statsig-sdk-a6f8881a1ad8" target="_blank" rel="noopener noreferrer">blog post about SDK evaluations</a>. If you have any questions, please ask them in our <a href="https://github.com/statsig-io/statsig-feedback/issues" target="_blank" rel="noopener noreferrer">Feedback Repository</a>.</div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="logging-an-event">Logging an Event<a href="#logging-an-event" class="hash-link" aria-label="Direct link to Logging an Event" title="Direct link to Logging an Event"></a></h3> Now that you have a Feature Gate or an Experiment set up, you may want to track some custom events and see how your new features or different experiment groups affect these events. This is super easy with Statsig - simply call the Log Event API and specify the user and event name to log; you additionally provide some value and/or an object of metadata to be logged together with the event: <div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">Statsig.logEvent(user, "add_to_cart", "SKU_12345", { price: "9.99", item_name: "diet_coke_48_pack", }); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div> Learn more about identifying users, group analytics, and best practices for logging events in the <a href="/guides/logging-events">logging events guide</a>. <h3 class="anchor anchorWithStickyNavbar_LWe7" id="retrieving-feature-gate-metadata">Retrieving Feature Gate Metadata<a href="#retrieving-feature-gate-metadata" class="hash-link" aria-label="Direct link to Retrieving Feature Gate Metadata" title="Direct link to Retrieving Feature Gate Metadata"></a></h3> In certain scenarios, you may need more information about a gate evaluation than just a boolean value. For additional metadata about the evaluation, use the Get Feature Gate API, which returns a FeatureGate object <div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">const showNewDesign = Statsig.getFeatureGate(user, 'new_homepage_design'); // using updated network values if (showNewDesign.value && showNewDesign.evaluationDetails?.reason === 'Network') { // show new design here } else { // show old design here } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div><div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="statsig-user">Statsig User<a href="#statsig-user" class="hash-link" aria-label="Direct link to Statsig User" title="Direct link to Statsig User"></a></h2> When calling APIs that require a user, you should pass as much information as possible in order to take advantage of advanced gate and config conditions (like country or OS/browser level checks), and correctly measure impact of your experiments on your metrics/events. The <code>userID</code> field is required because it's needed to provide a consistent experience for a given user (click <a href="/messages/serverRequiredUserID">here</a> to understand further why it's important to always provide a userID). Besides <code>userID</code>, we also have <code>email</code>, <code>ip</code>, <code>userAgent</code>, <code>country</code>, <code>locale</code> and <code>appVersion</code> as top-level fields on StatsigUser. In addition, you can pass any key-value pairs in an object/dictionary to the <code>custom</code> field and be able to create targeting based on them. Note that while typing is lenient on the <code>StatsigUser</code> object to allow you to pass in numbers, strings, arrays, objects, and potentially even enums or classes, the evaluation operators will only be able to operate on primitive types - mostly strings and numbers. While we attempt to smartly cast custom field types to match the operator, we cannot guarantee evaluation results for other types. For example, setting an array as a custom field will only ever be compared as a string - there is no operator to match a value in that array. <div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="private-attributes">Private Attributes<a href="#private-attributes" class="hash-link" aria-label="Direct link to Private Attributes" title="Direct link to Private Attributes"></a></h3> Have sensitive user PII data that should not be logged? No problem, we have a solution for it! On the StatsigUser object we also have a field called <code>privateAttributes</code>, which is a simple object/dictionary that you can use to set private user attributes. Any attribute set in <code>privateAttributes</code> will only be used for evaluation/targeting, and removed from any logs before they are sent to Statsig server. For example, if you have feature gates that should only pass for users with emails ending in "@statsig.com", but do not want to log your users' email addresses to Statsig, you can simply add the key-value pair <code>{ email: "my_user@statsig.com" }</code> to <code>privateAttributes</code> on the user and that's it!<div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="statsig-options">Statsig Options<a href="#statsig-options" class="hash-link" aria-label="Direct link to Statsig Options" title="Direct link to Statsig Options"></a></h2> <div><code>statsig.initialize()</code> takes an optional parameter <code>options</code> in addition to the secret key that you can provide to customize the Statsig client. Here are the current options and we are always adding more to the list: <ul> <li> api: string, default <code>https://statsigapi.net/v1</code> <ul> <li>The base url to use for all network requests. Defaults to the statsig API.</li> </ul> </li> <li> environment: StatsigEnvironment, default null <ul> <li>An object you can use to set environment variables that apply to all of your users in the same session and will be used for targeting purposes.</li> <li>The most common usage is to set the environment tier ('production', 'staging' or 'development'), e.g. <code>{ tier: 'staging' }</code>, and have feature gates pass/fail for specific environments. Since v6.0.0 default environment tier is production</li> </ul> </li> <li> bootstrapValues: string, default null <ul> <li>A string that represents all rules for all feature gates, dynamic configs and experiments. It can be provided to bootstrap the Statsig server SDK at initialization in case your server runs into network issue or Statsig server is down temporarily.</li> </ul> </li> <li> rulesUpdatedCallback: function, default null <ul> <li> A callback function that's called whenever we have an update for the rules; it's called with a JSON string (used as is for <code>bootstrapValues</code> mentioned above) and a timestamp, like below: <div class="codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-text codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">options.rulesUpdatedCallback(specsString, timeStamp) </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> </li> </ul> </li> <li> logger: LoggerInterface, default <code>console.log</code> <ul> <li>The logger interface to use for printing to stdout/stderr</li> </ul> </li> <li> localMode: boolean, default false <ul> <li> Pass true to this option to turn on Local Mode for the SDK, which will stop the SDK from issuing any network requests and make it only operate with only local overrides (If supported) and cache.<div>Note: Since no network requests will be made, a dummy SDK key starting with "secret-" can be used. (eg <code>"secret-key"</code>)</div> </li> <li>Disables all network access, so the SDK will only return default (or overridden) values. Useful in testing.</li> </ul> </li> <li> initTimeoutMs: number, default 0 <ul> <li>Sets a maximum time to wait for the config download network request to resolve before considering the SDK initialized and resolving the call to <code>initialize()</code></li> </ul> </li> <li> dataAdapter: IDataAdapter, default null <ul> <li>An adapter with custom storage behavior for config specs. Can be used to bootstrap Statsig server (takes priority over <code>bootstrapValues</code>). Can also be used to continuously fetch updates in place of the Statsig network. See <a href="/server/concepts/data_store">Data Stores</a>.</li> <li>For example, see our 1P implementation via Redis <a href="https://github.com/statsig-io/node-js-server-sdk-redis" target="_blank" rel="noopener noreferrer">statsig-node-redis</a>.</li> </ul> </li> <li> UserPersistentStorage: IUserPersistentStorage default nil <ul> <li>A persistent storage adapter for running sticky experiments. See <a href="/server/nodejsServerSDK#user-persistent-storage">examples</a>.</li> </ul> </li> <li> rulesetsSyncIntervalMs: number, default 10,000 <ul> <li>Sets the polling interval for the SDK to ask Statsig backend for changes on the rulesets.</li> </ul> </li> <li> idListsSyncIntervalMs: number, default 60,000 <ul> <li>Sets the polling interval for the SDK to ask Statsig backend for changes on the ID Lists.</li> </ul> </li> <li> loggingIntervalMs: number, default 60,000 <ul> <li>Sets the interval for the SDK to periodically flush all logging events to Statsig backend.</li> </ul> </li> <li> loggingMaxBufferSize: number, default 1,000 <ul> <li>Sets the maximum number of events the SDK's logger will batch before flushing them all to Statsig backend.</li> </ul> </li> <li> disableDiagnostics: boolean, default false <ul> <li>Disables diagnostics events from being logged and sent to Statsig</li> </ul> </li> <li> initStrategyForIP3Country: 'await' | 'lazy' | 'none', default 'await' <ul> <li>Method of initializing IP to country lookup on <code>statsig.initialize()</code>.</li> </ul> </li> <li> initStrategyForIDLists: 'await' | 'lazy' | 'none', default 'await' <ul> <li>Method of initializing ID lists on <code>statsig.initialize()</code>.</li> </ul> </li> <li> postLogsRetryLimit: number, default 5 <ul> <li>The maximum number of retry attempts when sending <code>/log_event</code> requests to Statsig server</li> </ul> </li> <li> postLogsRetryBackoff: number | (retry: number) => number, default 1,000 <ul> <li>A fixed number or callback on the retry attempt number to configure the time in ms to wait between each <code>/log_event</code> retry.</li> <li>If using a fixed number, a 10x multiplier will be applied on each subsequent retry</li> </ul> </li> </ul></div><div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="shutting-statsig-down">Shutting Statsig Down<a href="#shutting-statsig-down" class="hash-link" aria-label="Direct link to Shutting Statsig Down" title="Direct link to Shutting Statsig Down"></a></h2> Because we batch and periodically flush events, some events may not have been sent when your app/server shuts down. To make sure all logged events are properly flushed, you should tell Statsig to shutdown when your app/server is closing: <div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">statsig.shutdown(); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div> <div style="margin-bottom:15px;margin-top:30px">Alternatively, if you are operating in a serverless environment/cloud function, you may wish to leave Statsig running in case your function is recycled but flush the logs to Statsig servers. Or, if you need an async method to wait for logs to post before resolving, you can use:</div> <div><div class="language-js codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-js codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">await Statsig.flush(); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div><div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="bootstrap">Client SDK Bootstrapping | SSR v4.13.0+<a href="#bootstrap" class="hash-link" aria-label="Direct link to bootstrap" title="Direct link to bootstrap"></a></h2> <div style="margin-bottom:20px">The Node server SDK, starting in  <code>4.13.0</code> supports generating the  <code>initializeValues</code> needed to bootstrap a Statsig Client SDK preventing a round trip to Statsig servers. This can also be used with web [ <code>@statsig/js-client</code>, <code>@statsig/react-bindings</code>] SDKs to perform server side rendering (SSR).</div> <div class="language-swift codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-swift codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">const values = Statsig.getClientInitializeResponse(user); // Record<string, unknown> | null if (values != null) { // Bootstrap the Statsig React Client SDK return <StatsigSynchronousProvider initializeValues={values} ... />; } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="working-with-ip-or-useragent-values">Working with IP or UserAgent Values<a href="#working-with-ip-or-useragent-values" class="hash-link" aria-label="Direct link to Working with IP or UserAgent Values" title="Direct link to Working with IP or UserAgent Values"></a></h3> This will not automatically use the <code>ip</code>, or <code>userAgent</code> for gate evaluation as Statsig servers would, since there is no request from the client SDK specifying these values. If you want to use conditions like IP, or conditions which are inferred from the IP/UA like: Browser Name or Version, OS Name or Version, Country, you must manually set the <code>ip</code> and <code>userAgent</code> field on the user object when calling <code>getClientInitializeResponse</code>. <h3 class="anchor anchorWithStickyNavbar_LWe7" id="working-with-stableid">Working with stableID<a href="#working-with-stableid" class="hash-link" aria-label="Direct link to Working with stableID" title="Direct link to Working with stableID"></a></h3> There is no auto-generated <code>stableID</code> for device based experimentation, since the server generates the initialize response without any information from the client SDK. If you wish to run a device based experiment while using the server to generate the initialize response, we recommend you: <ol> <li>Create a customID in the Statsig console. See <a href="/guides/experiment-on-custom-id-types">experimenting on custom IDs</a> for more information.</li> <li>Generate an ID on the server, and set it in a cookie to be used on the client side as well.</li> <li>Set that ID as the customID on the <code>StatsigUser</code> object when generating the initialize response from the SDK.</li> <li>Get that ID from the cookie, and set it as the customID on the <code>StatsigUser</code> object when using the client SDK, so all event data and exposure checks tie back to the same user.</li> </ol> Alternatively, if you wish to use the <code>stableID</code> field rather than a custom ID, you still need to do step (2) above. Then: <ul> <li>Override the <code>stableID</code> in the client SDK by getting the value from the cookie and setting the <code>overrideStableID</code> parameter in <code>StatsigOptions</code></li> <li>Set the <code>stableID</code> field on the <code>StatsigUser</code> object in the <code>customIDs</code> map when generating the initialize response from the SDK</li> </ul><div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="local-overrides">Local Overrides v4.8.0+<a href="#local-overrides" class="hash-link" aria-label="Direct link to local-overrides" title="Direct link to local-overrides"></a></h2> If you want to locally override gates/configs/experiments/layers, there are a set of override APIs as follows. Coupling this with <a href="#statsig-options">StatsigOptions.localMode</a> can be useful when writing unit tests. <div class="tabs-container tabList__CuJ"><ul role="tablist" aria-orientation="horizontal" class="tabs"><li role="tab" tabindex="0" aria-selected="true" class="tabs__item tabItem_LNqP tabs__item--active">TypeScript</li><li role="tab" tabindex="-1" aria-selected="false" class="tabs__item tabItem_LNqP">JavaScript</li></ul><div class="margin-top--md"><div role="tabpanel" class="tabItem_Ymn6"><div class="language-swift codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-swift codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">// Overrides the given gate to the specified value Statsig.overrideGate("a_gate_name", true, "a_user_id"); // Overrides the given config (dynamic config or experiment) to the provided value Statsig.overrideConfig("a_config_or_experiment_name", { key: "value" }, "a_user_id"); // Overrides the given layer to the provided value Statsig.overrideLayer("a_layer_name", { key: "value" }, "a_user_id"); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div><div role="tabpanel" class="tabItem_Ymn6" hidden=""><div class="language-swift codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-swift codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">// Overrides the given gate to the specified value Statsig.overrideGate("a_gate_name", true, "a_user_id"); // Overrides the given config (dynamic config or experiment) to the provided value Statsig.overrideConfig("a_config_or_experiment_name", { key: "value" }, "a_user_id"); // Overrides the given layer to the provided value Statsig.overrideLayer("a_layer_name", { key: "value" }, "a_user_id"); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div></div></div> These can be used to set an override for a specific user, or for all users (by not providing a specific user ID). Experiments/Autotune are overridden with the <code>overrideConfig</code> API. <div class="theme-admonition theme-admonition-note admonition_xJq3 alert alert--secondary"><div class="admonitionHeading_Gvgb"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M6.3 5.69a.942.942 0 0 1-.28-.7c0-.28.09-.52.28-.7.19-.18.42-.28.7-.28.28 0 .52.09.7.28.18.19.28.42.28.7 0 .28-.09.52-.28.7a1 1 0 0 1-.7.3c-.28 0-.52-.11-.7-.3zM8 7.99c-.02-.25-.11-.48-.31-.69-.2-.19-.42-.3-.69-.31H6c-.27.02-.48.13-.69.31-.2.2-.3.44-.31.69h1v3c.02.27.11.5.31.69.2.2.42.31.69.31h1c.27 0 .48-.11.69-.31.2-.19.3-.42.31-.69H8V7.98v.01zM7 2.3c-3.14 0-5.7 2.54-5.7 5.68 0 3.14 2.56 5.7 5.7 5.7s5.7-2.55 5.7-5.7c0-3.15-2.56-5.69-5.7-5.69v.01zM7 .98c3.86 0 7 3.14 7 7s-3.14 7-7 7-7-3.12-7-7 3.14-7 7-7z"></path></svg>note</div><div class="admonitionContent_BuS1"><ol> <li>These only apply locally - they do not update definitions in the Statsig console or elsewhere.</li> <li>The local override API is not designed to be a full mock. They are only a convenient way to override the value of the gate/config/etc.</li> </ol></div></div><div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="manual-exposures-">Manual Exposures v5.0.0+<a href="#manual-exposures-" class="hash-link" aria-label="Direct link to manual-exposures-" title="Direct link to manual-exposures-"></a></h2> <div class="theme-admonition theme-admonition-warning admonition_xJq3 alert alert--warning"><div class="admonitionHeading_Gvgb"><svg viewBox="0 0 16 16"><path fill-rule="evenodd" d="M8.893 1.5c-.183-.31-.52-.5-.887-.5s-.703.19-.886.5L.138 13.499a.98.98 0 0 0 0 1.001c.193.31.53.501.886.501h13.964c.367 0 .704-.19.877-.5a1.03 1.03 0 0 0 .01-1.002L8.893 1.5zm.133 11.497H6.987v-2.003h2.039v2.003zm0-3.004H6.987V5.987h2.039v4.006z"></path></svg>warning</div><div class="admonitionContent_BuS1">Manually logging exposures can be tricky and may lead to an imbalance in exposure events. For example, only triggering exposures for users in the Test group of an experiment will imbalance the experiment, making it useless.</div></div> Added in version 5.0.0, you can now query your gates/experiments without triggering an exposure as well as manually logging your exposures. <div class="tabs-container tabList__CuJ"><ul role="tablist" aria-orientation="horizontal" class="tabs"><li role="tab" tabindex="0" aria-selected="true" class="tabs__item tabItem_LNqP tabs__item--active">Check Gate</li><li role="tab" tabindex="-1" aria-selected="false" class="tabs__item tabItem_LNqP">Get Config</li><li role="tab" tabindex="-1" aria-selected="false" class="tabs__item tabItem_LNqP">Get Experiment</li><li role="tab" tabindex="-1" aria-selected="false" class="tabs__item tabItem_LNqP">Get Layer</li></ul><div class="margin-top--md"><div role="tabpanel" class="tabItem_Ymn6">To check a gate without an exposure being logged, call the following.<div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">const result = Statsig.checkGate(aUser, 'a_gate_name', {disableExposureLogging: true}); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div>Later, if you would like to expose this gate, you can call the following.<div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">Statsig.manuallyLogGateExposure(aUser, 'a_gate_name'); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div></div><div role="tabpanel" class="tabItem_Ymn6" hidden="">To get a dynamic config without an exposure being logged, call the following.<div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">const config = Statsig.getConfigWithExposureLoggingDisabledSync(aUser, 'a_dynamic_config_name'); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div>Later, if you would like to expose the dynamic config, you can call the following.<div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">Statsig.manuallyLogConfigExposure(aUser, 'a_dynamic_config_name'); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div></div><div role="tabpanel" class="tabItem_Ymn6" hidden="">To get an experiment without an exposure being logged, call the following.<div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">const experiment = Statsig.getExperimentWithExposureLoggingDisabledSync(aUser, 'an_experiment_name'); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div>Later, if you would like to expose the experiment, you can call the following.<div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">Statsig.manuallyLogExperimentExposure(aUser, 'an_experiment_name'); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div></div><div role="tabpanel" class="tabItem_Ymn6" hidden="">To get a layer parameter without an exposure being logged, call the following.<div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">const layer = Statsig.getLayerWithExposureLoggingDisabledSync(aUser, 'a_layer_name'); const paramValue = layer.get('a_param_name', 'fallback_value'); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div>Later, if you would like to expose the layer parameter, you can call the following.<div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">Statsig.manuallyLogLayerParameterExposure(aUser, 'a_layer_name', 'a_param_name'); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div></div></div></div><div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="environment-specific-setup">Environment Specific Setup<a href="#environment-specific-setup" class="hash-link" aria-label="Direct link to Environment Specific Setup" title="Direct link to Environment Specific Setup"></a></h2> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="cloudflare">Cloudflare<a href="#cloudflare" class="hash-link" aria-label="Direct link to Cloudflare" title="Direct link to Cloudflare"></a></h3> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="polling-for-updates-">Polling for updates v5.13.0+<a href="#polling-for-updates-" class="hash-link" aria-label="Direct link to polling-for-updates-" title="Direct link to polling-for-updates-"></a></h4> The SDK cannot poll for updates across requests since Cloudflare does not allow for timers<a href="https://developers.cloudflare.com/workers/reference/security-model/#step-1-disallow-timers-and-multi-threading" target="_blank" rel="noopener noreferrer">**</a>. To solve for this, a manual sync API is available for independently updating the SDK internal store. <div class="language-javascript codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-javascript codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">if (env.lastSyncTime < Date.now() - env.syncInterval) { env.lastSyncTime = Date.now(); context.waitUntil(Statsig.syncConfigSpecs()); } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="flushing-events-">Flushing events v4.16.0+<a href="#flushing-events-" class="hash-link" aria-label="Direct link to flushing-events-" title="Direct link to flushing-events-"></a></h4> The SDK enqueues logged events and flushes them in batches. In order to ensure events are properly flushed, we recommend calling <code>flush</code> using <a href="https://developers.cloudflare.com/workers/runtime-apis/handlers/fetch/#contextwaituntil" target="_blank" rel="noopener noreferrer"><code>context.waitUntil</code></a>. This will keep the request handler alive until events are flushed without blocking the response. <div class="language-javascript codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-javascript codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">context.waitUntil(Statsig.flush()); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="nodejs-compatibility-">Node.JS Compatibility v5.16.0+<a href="#nodejs-compatibility-" class="hash-link" aria-label="Direct link to nodejs-compatibility-" title="Direct link to nodejs-compatibility-"></a></h4> Many native JavaScript API and Node standard libraries can be accessed in Cloudflare via the <a href="https://developers.cloudflare.com/workers/runtime-apis/nodejs/" target="_blank" rel="noopener noreferrer"><code>nodejs_compat</code></a> compatibility flag. The SDK is now compatible with <code>nodejs_compat</code> (since v5.16.0). In older versions, manual polyfilling is required.<div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="user-persistent-storage">User Persistent Storage<a href="#user-persistent-storage" class="hash-link" aria-label="Direct link to User Persistent Storage" title="Direct link to User Persistent Storage"></a></h2> A custom storage adapter that allows the SDK the persist values for users in active experiments. In other words, allowing you to run experiments with sticky bucketing. You can provide a persistent storage adapter via <a href="#statsig-options">StatsigOptions.UserPersistentStorage</a>. You can read more about the concept <a href="/server/concepts/persistent_assignment">here</a>. <h3 class="anchor anchorWithStickyNavbar_LWe7" id="storage-interface">Storage Interface<a href="#storage-interface" class="hash-link" aria-label="Direct link to Storage Interface" title="Direct link to Storage Interface"></a></h3> You can write you own custom storage that implements the following interface: <div class="language-ts codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-ts codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">export interface IUserPersistentStorage { /** * Returns the full map of persisted values for a specific user key * @param key user key */ load(key: string): UserPersistedValues; /** * Save the persisted values of a config given a specific user key * @param key user key * @param configName Name of the config/experiment * @param data Object representing the persistent assignment to store for the given user-config */ save(key: string, configName: string, data: StickyValues): void; /** * Delete the persisted values of a config given a specific user key * @param key user key * @param configName Name of the config/experiment */ delete(key: string, configName: string): void; } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="example-implementation">Example Implementation<a href="#example-implementation" class="hash-link" aria-label="Direct link to Example Implementation" title="Direct link to Example Implementation"></a></h3> <div class="language-ts codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-ts codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class UserPersistentStorageExample implements IUserPersistentStorage { public store: Record<string, UserPersistedValues> = {}; load(key: string): UserPersistedValues { return this.store[key]; } save(key: string, configName: string, data: StickyValues): void { if (!(key in this.store)) { this.store[key] = {}; } this.store[key][configName] = data; } delete(key: string, configName: string): void { delete this.store[key][configName]; } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div><div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="multiple-statsig-sdk-instances">Multiple Statsig SDK Instances<a href="#multiple-statsig-sdk-instances" class="hash-link" aria-label="Direct link to Multiple Statsig SDK Instances" title="Direct link to Multiple Statsig SDK Instances"></a></h2> Our documentation up to this point guides you through setting up your Statsig integration via the singleton Statsig. There are cases where you may need to create multiple instances of the Statsig SDK. Each SDK supports this as well - the Statsig singleton wraps a single instance of the SDK that you can instantiate. NOTE: currently all sdk instances will use the same keys when interacting with a <a href="/server/concepts/data_store">Data Store/Data Adapter</a>. You will not be able to isolate multiple instances of the sdk in your data store. All top level static methods from the singleton carry over as instance methods. To create an instance of the Statsig sdk: <div><div class="language-jsx codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-jsx codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">// Statsig.initialize becomes: const sdkInstance = new StatsigServer(secretKey, options); await sdkInstance.initializeAsync(); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div><div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="proxy-configurations-">Proxy Configurations v5.21.1-beta.2z+<a href="#proxy-configurations-" class="hash-link" aria-label="Direct link to proxy-configurations-" title="Direct link to proxy-configurations-"></a></h2> Advance SDK Network setup, provide options to configure network protocol and proxy address for individual network endpoint. This option is provided for better integration with <a href="/server/concepts/forward_proxy">Statsig Forward Proxy</a> <div><h4 class="anchor anchorWithStickyNavbar_LWe7" id="authentication-">Authentication <a href="#authentication-" class="hash-link" aria-label="Direct link to authentication-" title="Direct link to authentication-"></a></h4>With more advanced requirements on security, we also support TLS and mTLS for grpc streaming (<code>protocol=GRPC_WEBSOCKET</code>) You need to configure ProxyConfig for each endpoint</div> <div><div><h4>Installation</h4>We are still in the testing phase of this feature. Package deployment / installation will be different.<div>The Beta SDK is hosted <a href="https://www.npmjs.com/package/statsig-node/v/5.21.1-beta.2?activeTab=readme" target="_blank" rel="noopener noreferrer">here</a>. You can install the SDK using NPM or Yarn: <div class="tabs-container tabList__CuJ"><ul role="tablist" aria-orientation="horizontal" class="tabs"><li role="tab" tabindex="0" aria-selected="true" class="tabs__item tabItem_LNqP tabs__item--active">NPM</li><li role="tab" tabindex="-1" aria-selected="false" class="tabs__item tabItem_LNqP">Yarn</li></ul><div class="margin-top--md"><div role="tabpanel" class="tabItem_Ymn6"><div class="language-shell codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-shell codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">npm i statsig-node@5.21.1-beta.2 </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div><div role="tabpanel" class="tabItem_Ymn6" hidden=""><div class="language-shell codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-shell codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">yarn add statsig-node@5.21.1-beta.2 </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div></div></div></div></div></div> <h4>Initialization</h4> To setup grpc streaming for download config spec. And use default behavior for get_id_lists and log_events endpoints. <div><div class="language-js codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-js codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">const proxyAddress = "0.0.0.0:50051" const options = { proxyConfigs: { 'download_config_specs': { "proxyAddress": proxyAddress, "protocol": "grpc_websocket" as NetworkProtocol } } } await Statsig.initialize(secretKey, options) </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div></div><div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="faq">FAQ<a href="#faq" class="hash-link" aria-label="Direct link to FAQ" title="Direct link to FAQ"></a></h2> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="logged-out-experiments">How do I run experiments for logged out users?<a href="#logged-out-experiments" class="hash-link" aria-label="Direct link to How do I run experiments for logged out users?" title="Direct link to How do I run experiments for logged out users?"></a></h4> See the guide on <a href="/guides/first-device-level-experiment">device level experiments</a> <div><h4 class="anchor anchorWithStickyNavbar_LWe7" id="ssr">How can I use the node SDK for server side rendering?<a href="#ssr" class="hash-link" aria-label="Direct link to How can I use the node SDK for server side rendering?" title="Direct link to How can I use the node SDK for server side rendering?"></a></h4> See <a href="#bootstrap">Client SDK Bootstrapping | SSR</a> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="how-can-i-mock-statsig-for-testing">How can I mock Statsig for testing?<a href="#how-can-i-mock-statsig-for-testing" class="hash-link" aria-label="Direct link to How can I mock Statsig for testing?" title="Direct link to How can I mock Statsig for testing?"></a></h4> See <a href="#local-overrides">LocalOverrides</a></div><div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="reference">Reference<a href="#reference" class="hash-link" aria-label="Direct link to Reference" title="Direct link to Reference"></a></h2> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="type-statsiguser">Type StatsigUser<a href="#type-statsiguser" class="hash-link" aria-label="Direct link to Type StatsigUser" title="Direct link to Type StatsigUser"></a></h3> <div class="language-typescript codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-typescript codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">export type StatsigUser = // at least one of userID or customIDs must be provided ({ userID: string } | { customIDs: Record<string, string> }) & { userID?: string; customIDs?: Record<string, string>; email?: string; ip?: string; userAgent?: string; country?: string; locale?: string; appVersion?: string; custom?: Record< string, string | number | boolean | Array<string> | undefined >; privateAttributes?: Record< string, string | number | boolean | Array<string> | undefined > | null; statsigEnvironment?: StatsigEnvironment; } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="type-statsigoptions">Type StatsigOptions<a href="#type-statsigoptions" class="hash-link" aria-label="Direct link to Type StatsigOptions" title="Direct link to Type StatsigOptions"></a></h3> <div class="language-typescript codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-typescript codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">export type StatsigOptions = { api: string; apiForDownloadConfigSpecs: string; apiForGetIdLists: string; bootstrapValues: string | null; environment: StatsigEnvironment | null; rulesUpdatedCallback: RulesUpdatedCallback | null; logger: LoggerInterface; localMode: boolean; initTimeoutMs: number; dataAdapter: IDataAdapter | null; rulesetsSyncIntervalMs: number; idListsSyncIntervalMs: number; loggingIntervalMs: number; loggingMaxBufferSize: number; disableDiagnostics: boolean; initStrategyForIP3Country: InitStrategy; initStrategyForIDLists: InitStrategy; postLogsRetryLimit: number; postLogsRetryBackoff: RetryBackoffFunc | number; disableRulesetsSync: boolean; disableIdListsSync: boolean; disableAllLogging: boolean; }; export type RulesUpdatedCallback = (rulesJSON: string, time: number) => void; export type RetryBackoffFunc = (retriesRemaining: number) => number; export type StatsigEnvironment = { tier?: 'production' | 'staging' | 'development' | string; [key: string]: string | undefined; }; export type InitStrategy = 'await' | 'lazy' | 'none'; export interface LoggerInterface { debug?(message?: any, ...optionalParams: any[]): void; info?(message?: any, ...optionalParams: any[]): void; warn(message?: any, ...optionalParams: any[]): void; error(message?: any, ...optionalParams: any[]): void; logLevel: 'none' | 'debug' | 'info' | 'warn' | 'error'; } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="type-statsigenvironment">Type StatsigEnvironment<a href="#type-statsigenvironment" class="hash-link" aria-label="Direct link to Type StatsigEnvironment" title="Direct link to Type StatsigEnvironment"></a></h3> <div class="language-typescript codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-typescript codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">export type StatsigEnvironment = { tier?: "production" | "staging" | "development"; bootstrapValues: string; rulesUpdatedCallback: function; }; </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="type-featuregate">Type FeatureGate<a href="#type-featuregate" class="hash-link" aria-label="Direct link to Type FeatureGate" title="Direct link to Type FeatureGate"></a></h3> <div class="language-typescript codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-typescript codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">export type FeatureGate = { readonly name: string; readonly ruleID: string; readonly idType: string | null; readonly value: boolean; readonly evaluationDetails: EvaluationDetails | null; readonly groupName: null; // deprecated }; </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="type-dynamicconfig">Type DynamicConfig<a href="#type-dynamicconfig" class="hash-link" aria-label="Direct link to Type DynamicConfig" title="Direct link to Type DynamicConfig"></a></h3> <div class="language-typescript codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-typescript codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">export default class DynamicConfig { name: string; value: Record<string, unknown>; get<T>( key: string, defaultValue: T, typeGuard: ((value: unknown) => value is T | null) | null = null, ): T; getValue( key: string, defaultValue?: boolean | number | string | object | Array<any> | null, ): unknown | null; getRuleID(): string; getGroupName(): string | null; getIDType(): string | null; getEvaluationDetails(): EvaluationDetails | null; </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="type-layer">Type Layer<a href="#type-layer" class="hash-link" aria-label="Direct link to Type Layer" title="Direct link to Type Layer"></a></h3> <div class="language-typescript codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-typescript codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">export default class Layer { name: string; public get<T>( key: string, defaultValue: T, typeGuard: ((value: unknown) => value is T) | null = null, ): T; getValue( key: string, defaultValue?: boolean | number | string | object | Array<any> | null, ): unknown | null; getRuleID(): string; getGroupName(): string | null; getAllocatedExperimentName(): string | null; getEvaluationDetails(): EvaluationDetails | null; </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="dataadapter">DataAdapter<a href="#dataadapter" class="hash-link" aria-label="Direct link to DataAdapter" title="Direct link to DataAdapter"></a></h3> <div class="language-typescript codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-typescript codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">export interface IDataAdapter { get(key: string): Promise<AdapterResponse>; set(key: string, value: string, time?: number): Promise<void>; initialize(): Promise<void>; shutdown(): Promise<void>; supportsPollingUpdatesFor(key: DataAdapterKey): boolean; } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="evaluationdetails">EvaluationDetails<a href="#evaluationdetails" class="hash-link" aria-label="Direct link to EvaluationDetails" title="Direct link to EvaluationDetails"></a></h3> <div class="language-typescript codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-typescript codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">export class EvaluationDetails { readonly configSyncTime: number; readonly initTime: number; readonly serverTime: number; readonly reason: EvaluationReason; } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="evaluationreason">EvaluationReason<a href="#evaluationreason" class="hash-link" aria-label="Direct link to EvaluationReason" title="Direct link to EvaluationReason"></a></h3> <div class="language-typescript codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-typescript codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">export type EvaluationReason = | 'Network' | 'LocalOverride' | 'Unrecognized' | 'Uninitialized' | 'Bootstrap' | 'DataAdapter' | 'Unsupported'; </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div><div style="height:4px"></div><h2 class="anchor anchorWithStickyNavbar_LWe7" id="major-version-upgrade-guide">Major Version Upgrade Guide<a href="#major-version-upgrade-guide" class="hash-link" aria-label="Direct link to Major Version Upgrade Guide" title="Direct link to Major Version Upgrade Guide"></a></h2>  <ul><a href="/server/nodejsServerSDK/upgrade_guide/v5ToV6"><li>V5.x.x to V6.x.x</li></a></ul><div style="height:4px"></div></div><footer class="theme-doc-footer docusaurus-mt-lg"><div class="row margin-top--sm theme-doc-footer-edit-meta-row"><div class="col"><a href="https://github.com/statsig-io/docs/edit/main/docs/server/nodejsServerSDK.mdx" target="_blank" rel="noopener noreferrer" class="theme-edit-this-page"><svg fill="currentColor" height="20" width="20" viewBox="0 0 40 40" class="iconEdit_Z9Sw" aria-hidden="true"><g><path d="m34.5 11.7l-3 3.1-6.3-6.3 3.1-3q0.5-0.5 1.2-0.5t1.1 0.5l3.9 3.9q0.5 0.4 0.5 1.1t-0.5 1.2z m-29.5 17.1l18.4-18.5 6.3 6.3-18.4 18.4h-6.3v-6.2z"></path></g></svg>Edit this page</a></div><div class="col lastUpdated_JAkA">Last updated on <time datetime="2024-11-18T19:07:50.000Z" itemprop="dateModified">Nov 18, 2024</time></div></div></footer></article><nav class="pagination-nav docusaurus-mt-lg" aria-label="Docs pages"><a class="pagination-nav__link pagination-nav__link--prev" href="/client/javascript-sdk/next-js"><div class="pagination-nav__sublabel">Previous</div><div class="pagination-nav__label">Next.js</div></a><a class="pagination-nav__link pagination-nav__link--next" href="/client/cpp-client-sdk"><div class="pagination-nav__sublabel">Next</div><div class="pagination-nav__label">C++ Client</div></a></nav></div></div><div class="col col--3"><div class="tableOfContents_bqdL thin-scrollbar theme-doc-toc-desktop"><ul class="table-of-contents table-of-contents__left-border"><li><a href="#0" class="table-of-contents__link toc-highlight"><div id="sdk-toc-header" x-last-updated="undefined"><div style="min-height: 65px; cursor: default; padding: 10px 20px; background-color: var(--ifm-navbar-background-color); border-radius: 10px; font-size: 12px; margin-bottom: 15px; color: var(--ifm-color-content);">...</div></div></a></li><li><a href="#installation" class="table-of-contents__link toc-highlight">Installation</a></li><li><a href="#initialize-the-sdk" class="table-of-contents__link toc-highlight">Initialize the SDK</a></li><li><a href="#working-with-the-sdk" class="table-of-contents__link toc-highlight">Working with the SDK</a><ul><li><a href="#checking-a-feature-flaggate" class="table-of-contents__link toc-highlight">Checking a Feature Flag/Gate</a></li><li><a href="#reading-a-dynamic-config" class="table-of-contents__link toc-highlight">Reading a Dynamic Config</a></li><li><a href="#getting-an-layerexperiment" class="table-of-contents__link toc-highlight">Getting an Layer/Experiment</a></li><li><a href="#logging-an-event" class="table-of-contents__link toc-highlight">Logging an Event</a></li><li><a href="#retrieving-feature-gate-metadata" class="table-of-contents__link toc-highlight">Retrieving Feature Gate Metadata</a></li></ul></li><li><a href="#statsig-user" class="table-of-contents__link toc-highlight">Statsig User</a><ul><li><a href="#private-attributes" class="table-of-contents__link toc-highlight">Private Attributes</a></li></ul></li><li><a href="#statsig-options" class="table-of-contents__link toc-highlight">Statsig Options</a></li><li><a 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