The most effective ways to improve Core Web Vitals | Articles

<!doctype html> <html lang="en" dir="ltr"> <head> <meta name="google-signin-client-id" content="157101835696-ooapojlodmuabs2do2vuhhnf90bccmoi.apps.googleusercontent.com"> <meta name="google-signin-scope" content="profile email https://www.googleapis.com/auth/developerprofiles https://www.googleapis.com/auth/developerprofiles.award"> <meta property="og:site_name" content="web.dev"> <meta property="og:type" content="website"><meta name="theme-color" content="#3740ff"><meta charset="utf-8"> <meta content="IE=Edge" http-equiv="X-UA-Compatible"> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="manifest" href="/_pwa/web/manifest.json" crossorigin="use-credentials"> <link rel="preconnect" href="//www.gstatic.com" crossorigin> <link rel="preconnect" href="//fonts.gstatic.com" crossorigin> <link rel="preconnect" href="//fonts.googleapis.com" crossorigin> <link rel="preconnect" href="//apis.google.com" crossorigin> <link rel="preconnect" href="//www.google-analytics.com" crossorigin><link rel="stylesheet" href="//fonts.googleapis.com/css?family=Google+Sans:400,500|Roboto:400,400italic,500,500italic,700,700italic|Roboto+Mono:400,500,700&display=swap"> <link rel="stylesheet" href="//fonts.googleapis.com/css2?family=Material+Icons&family=Material+Symbols+Outlined&display=block"><link rel="stylesheet" href="https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625/web/css/app.css"> <link rel="stylesheet" href="https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625/web/css/dark-theme.css" disabled> <link rel="shortcut icon" href="https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625/web/images/favicon.png"> <link rel="apple-touch-icon" href="https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625/web/images/touchicon-180.png"><link rel="canonical" href="https://web.dev/articles/top-cwv"><link rel="search" type="application/opensearchdescription+xml" title="web.dev" href="https://web.dev/s/opensearch.xml"> <link rel="alternate" hreflang="en" href="https://web.dev/articles/top-cwv" /><link rel="alternate" hreflang="x-default" href="https://web.dev/articles/top-cwv" /><link rel="alternate" hreflang="ar" href="https://web.dev/articles/top-cwv?hl=ar" /><link rel="alternate" hreflang="bn" href="https://web.dev/articles/top-cwv?hl=bn" /><link rel="alternate" hreflang="zh-Hans" href="https://web.dev/articles/top-cwv?hl=zh-cn" /><link rel="alternate" hreflang="zh-Hant" href="https://web.dev/articles/top-cwv?hl=zh-tw" /><link rel="alternate" hreflang="fa" href="https://web.dev/articles/top-cwv?hl=fa" /><link rel="alternate" hreflang="fr" href="https://web.dev/articles/top-cwv?hl=fr" /><link rel="alternate" hreflang="de" href="https://web.dev/articles/top-cwv?hl=de" /><link rel="alternate" hreflang="he" href="https://web.dev/articles/top-cwv?hl=he" /><link rel="alternate" hreflang="hi" href="https://web.dev/articles/top-cwv?hl=hi" /><link rel="alternate" hreflang="id" href="https://web.dev/articles/top-cwv?hl=id" /><link rel="alternate" hreflang="it" href="https://web.dev/articles/top-cwv?hl=it" /><link rel="alternate" hreflang="ja" href="https://web.dev/articles/top-cwv?hl=ja" /><link rel="alternate" hreflang="ko" href="https://web.dev/articles/top-cwv?hl=ko" /><link rel="alternate" hreflang="pl" href="https://web.dev/articles/top-cwv?hl=pl" /><link rel="alternate" hreflang="pt-BR" href="https://web.dev/articles/top-cwv?hl=pt-br" /><link rel="alternate" hreflang="ru" href="https://web.dev/articles/top-cwv?hl=ru" /><link rel="alternate" hreflang="es-419" href="https://web.dev/articles/top-cwv?hl=es-419" /><link rel="alternate" hreflang="th" href="https://web.dev/articles/top-cwv?hl=th" /><link rel="alternate" hreflang="tr" href="https://web.dev/articles/top-cwv?hl=tr" /><link rel="alternate" hreflang="vi" href="https://web.dev/articles/top-cwv?hl=vi" /><link rel="alternate" hreflang="en-cn" href="https://web.developers.google.cn/articles/top-cwv" /><link rel="alternate" hreflang="x-default" href="https://web.developers.google.cn/articles/top-cwv" /><link rel="alternate" hreflang="ar-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=ar" /><link rel="alternate" hreflang="bn-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=bn" /><link rel="alternate" hreflang="zh-Hans-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=zh-cn" /><link rel="alternate" hreflang="zh-Hant-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=zh-tw" /><link rel="alternate" hreflang="fa-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=fa" /><link rel="alternate" hreflang="fr-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=fr" /><link rel="alternate" hreflang="de-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=de" /><link rel="alternate" hreflang="he-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=he" /><link rel="alternate" hreflang="hi-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=hi" /><link rel="alternate" hreflang="id-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=id" /><link rel="alternate" hreflang="it-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=it" /><link rel="alternate" hreflang="ja-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=ja" /><link rel="alternate" hreflang="ko-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=ko" /><link rel="alternate" hreflang="pl-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=pl" /><link rel="alternate" hreflang="pt-BR-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=pt-br" /><link rel="alternate" hreflang="ru-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=ru" /><link rel="alternate" hreflang="es-419-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=es-419" /><link rel="alternate" hreflang="th-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=th" /><link rel="alternate" hreflang="tr-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=tr" /><link rel="alternate" hreflang="vi-cn" href="https://web.developers.google.cn/articles/top-cwv?hl=vi" /><title>The most effective ways to improve Core Web Vitals  |  Articles  |  web.dev</title> <meta property="og:title" content="The most effective ways to improve Core Web Vitals  |  Articles  |  web.dev"><meta name="description" content="A collection of best practices that Chrome has identified as the biggest opportunities to optimize web performance and improve Core Web Vitals"> <meta property="og:description" content="A collection of best practices that Chrome has identified as the biggest opportunities to optimize web performance and improve Core Web Vitals"><meta property="og:url" content="https://web.dev/articles/top-cwv"><meta property="og:image" content="https://web.dev/static/articles/top-cwv/image/top-cwv.png"> <meta property="og:image:width" content="1200"> <meta property="og:image:height" content="675"><meta property="og:locale" content="en"><meta name="twitter:card" content="summary_large_image"><script type="application/ld+json"> { "@context": "https://schema.org", "@type": "Article", "dateModified": "2024-10-31", "headline": "The most effective ways to improve Core Web Vitals" } </script><script type="application/ld+json"> { "@context": "https://schema.org", "@type": "BreadcrumbList", "itemListElement": [{ "@type": "ListItem", "position": 1, "name": "Articles", "item": "https://web.dev/articles" },{ "@type": "ListItem", "position": 2, "name": "The most effective ways to improve Core Web Vitals", "item": "https://web.dev/articles/top-cwv" }] } </script> <link rel="stylesheet" href="/extras.css"></head> <body class="" template="page" theme="web-theme" type="article" appearance layout="docs" display-toc pending> <devsite-progress type="indeterminate" id="app-progress"></devsite-progress> <section class="devsite-wrapper"> <devsite-cookie-notification-bar></devsite-cookie-notification-bar><devsite-header role="banner"> <div class="devsite-header--inner nocontent"> <div class="devsite-top-logo-row-wrapper-wrapper"> <div class="devsite-top-logo-row-wrapper"> <div class="devsite-top-logo-row"> <button type="button" id="devsite-hamburger-menu" class="devsite-header-icon-button button-flat material-icons gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Navigation menu button" visually-hidden aria-label="Open menu"> </button> <div class="devsite-product-name-wrapper"> <a href="/" class="devsite-site-logo-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Site logo" track-type="globalNav" track-name="webDev" track-metadata-position="nav" track-metadata-eventDetail="nav"> <picture> <source srcset="https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625/web/images/lockup-dark-theme.svg" media="(prefers-color-scheme: dark)" class="devsite-dark-theme" alt="web.dev"> <img src="https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625/web/images/lockup.svg" class="devsite-site-logo" alt="web.dev"> </picture> </a> <span class="devsite-product-name"> <ul class="devsite-breadcrumb-list" > <li class="devsite-breadcrumb-item "> </li> </ul> </span> </div> <div class="devsite-top-logo-row-middle"> <div class="devsite-header-upper-tabs"> <devsite-tabs class="upper-tabs"> <nav class="devsite-tabs-wrapper" aria-label="Upper tabs"> <tab > <a href="https://web.dev/about" track-metadata-eventdetail="https://web.dev/about" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - about" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: About" track-name="about" > About </a> </tab> <tab > <a href="https://web.dev/html" track-metadata-eventdetail="https://web.dev/html" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - html" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: HTML" track-name="html" > HTML </a> </tab> <tab > <a href="https://web.dev/css" track-metadata-eventdetail="https://web.dev/css" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - css" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: CSS" track-name="css" > CSS </a> </tab> <tab > <a href="https://web.dev/javascript" track-metadata-eventdetail="https://web.dev/javascript" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - javascript" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: JavaScript" track-name="javascript" > JavaScript </a> </tab> <tab > <a href="https://web.dev/blog" track-metadata-eventdetail="https://web.dev/blog" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - blog" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Blog" track-name="blog" > Blog </a> </tab> <tab > <a href="https://web.dev/learn" track-metadata-eventdetail="https://web.dev/learn" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - learn" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Learn" track-name="learn" > Learn </a> </tab> <tab class="devsite-active"> <a href="https://web.dev/explore" track-metadata-eventdetail="https://web.dev/explore" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - explore" track-metadata-module="primary nav" aria-label="Explore, selected" data-category="Site-Wide Custom Events" data-label="Tab: Explore" track-name="explore" > Explore </a> </tab> <tab > <a href="https://web.dev/patterns" track-metadata-eventdetail="https://web.dev/patterns" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - patterns" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Patterns" track-name="patterns" > Patterns </a> </tab> <tab > <a href="https://web.dev/case-studies" track-metadata-eventdetail="https://web.dev/case-studies" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - case studies" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Case studies" track-name="case studies" > Case studies </a> </tab> </nav> </devsite-tabs> </div> <devsite-search enable-signin enable-search enable-suggestions enable-query-completion project-name="Articles" tenant-name="web.dev" > <form class="devsite-search-form" action="https://web.dev/s/results" method="GET"> <div class="devsite-search-container"> <button type="button" search-open class="devsite-search-button devsite-header-icon-button button-flat material-icons" aria-label="Open search"></button> <div class="devsite-searchbox"> <input aria-activedescendant="" aria-autocomplete="list" aria-label="Search" aria-expanded="false" aria-haspopup="listbox" autocomplete="off" class="devsite-search-field devsite-search-query" name="q" placeholder="Search" role="combobox" type="text" value="" > <div class="devsite-search-image material-icons" aria-hidden="true"> </div> <div class="devsite-search-shortcut-icon-container" aria-hidden="true"> <kbd class="devsite-search-shortcut-icon">/</kbd> </div> </div> </div> </form> <button type="button" search-close class="devsite-search-button devsite-header-icon-button button-flat material-icons" aria-label="Close search"></button> </devsite-search> </div> <devsite-appearance-selector></devsite-appearance-selector> <devsite-language-selector> <ul role="presentation"> <li role="presentation"> <a role="menuitem" lang="en" >English</a> </li> <li role="presentation"> <a role="menuitem" lang="de" >Deutsch</a> </li> <li role="presentation"> <a role="menuitem" lang="es_419" >Español – América Latina</a> </li> <li role="presentation"> <a role="menuitem" lang="fr" >Français</a> </li> <li role="presentation"> <a role="menuitem" lang="id" >Indonesia</a> </li> <li role="presentation"> <a role="menuitem" lang="it" >Italiano</a> </li> <li role="presentation"> <a role="menuitem" lang="pl" >Polski</a> </li> <li role="presentation"> <a role="menuitem" lang="pt_br" >Português – Brasil</a> </li> <li role="presentation"> <a role="menuitem" lang="vi" >Tiếng Việt</a> </li> <li role="presentation"> <a role="menuitem" lang="tr" >Türkçe</a> </li> <li role="presentation"> <a role="menuitem" lang="ru" >Русский</a> </li> <li role="presentation"> <a role="menuitem" lang="he" >עברית</a> </li> <li role="presentation"> <a role="menuitem" lang="ar" >العربيّة</a> </li> <li role="presentation"> <a role="menuitem" lang="fa" >فارسی</a> </li> <li role="presentation"> <a role="menuitem" lang="hi" >हिंदी</a> </li> <li role="presentation"> <a role="menuitem" lang="bn" >বাংলা</a> </li> <li role="presentation"> <a role="menuitem" lang="th" >ภาษาไทย</a> </li> <li role="presentation"> <a role="menuitem" lang="zh_cn" >中文 – 简体</a> </li> <li role="presentation"> <a role="menuitem" lang="zh_tw" >中文 – 繁體</a> </li> <li role="presentation"> <a role="menuitem" lang="ja" >日本語</a> </li> <li role="presentation"> <a role="menuitem" lang="ko" >한국어</a> </li> </ul> </devsite-language-selector> <devsite-user enable-profiles id="devsite-user"> <span class="button devsite-top-button" aria-hidden="true" visually-hidden>Sign in</span> </devsite-user> </div> </div> </div> <div class="devsite-collapsible-section "> <div class="devsite-header-background"> <div class="devsite-product-id-row" > <div class="devsite-product-description-row"> <ul class="devsite-breadcrumb-list" > <li class="devsite-breadcrumb-item "> <a href="https://web.dev/explore" class="devsite-breadcrumb-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Lower Header" data-value="1" track-type="globalNav" track-name="breadcrumb" track-metadata-position="1" track-metadata-eventdetail="" > Collections </a> </li> </ul> </div> </div> <div class="devsite-doc-set-nav-row"> <devsite-tabs class="lower-tabs"> <nav class="devsite-tabs-wrapper" aria-label="Lower tabs"> <tab > <a href="https://web.dev/explore/learn-core-web-vitals" track-metadata-eventdetail="https://web.dev/explore/learn-core-web-vitals" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - core web vitals" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Core Web Vitals" track-name="core web vitals" > Core Web Vitals </a> </tab> <tab > <a href="https://web.dev/explore/metrics" track-metadata-eventdetail="https://web.dev/explore/metrics" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - metrics" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Metrics" track-name="metrics" > Metrics </a> </tab> <tab class="devsite-active"> <a href="https://web.dev/explore/fast" track-metadata-eventdetail="https://web.dev/explore/fast" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - fast load times" track-metadata-module="primary nav" aria-label="Fast load times, selected" data-category="Site-Wide Custom Events" data-label="Tab: Fast load times" track-name="fast load times" > Fast load times </a> </tab> <tab > <a href="https://web.dev/explore/ai" track-metadata-eventdetail="https://web.dev/explore/ai" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - ai" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: AI" track-name="ai" > AI </a> </tab> <tab > <a href="https://web.dev/explore/how-to-optimize-inp" track-metadata-eventdetail="https://web.dev/explore/how-to-optimize-inp" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - optimize interaction to next paint (inp)" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Optimize Interaction to Next Paint (INP)" track-name="optimize interaction to next paint (inp)" > Optimize Interaction to Next Paint (INP) </a> </tab> <tab > <a href="https://web.dev/explore/progressive-web-apps" track-metadata-eventdetail="https://web.dev/explore/progressive-web-apps" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - progressive web apps" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Progressive Web Apps" track-name="progressive web apps" > Progressive Web Apps </a> </tab> <tab > <a href="https://web.dev/accessibility" track-metadata-eventdetail="https://web.dev/accessibility" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - accessible to all" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Accessible to all" track-name="accessible to all" > Accessible to all </a> </tab> <tab > <a href="https://web.dev/explore/reliable" track-metadata-eventdetail="https://web.dev/explore/reliable" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - network reliability" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Network reliability" track-name="network reliability" > Network reliability </a> </tab> <tab > <a href="https://web.dev/explore/secure" track-metadata-eventdetail="https://web.dev/explore/secure" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - safe and secure" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Safe and secure" track-name="safe and secure" > Safe and secure </a> </tab> <tab > <a href="https://web.dev/explore/discoverable" track-metadata-eventdetail="https://web.dev/explore/discoverable" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - easily discoverable" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Easily discoverable" track-name="easily discoverable" > Easily discoverable </a> </tab> <tab > <a href="https://web.dev/explore/payments" track-metadata-eventdetail="https://web.dev/explore/payments" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - web payments" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Web Payments" track-name="web payments" > Web Payments </a> </tab> <tab > <a href="https://web.dev/explore/media" track-metadata-eventdetail="https://web.dev/explore/media" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - media" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Media" track-name="media" > Media </a> </tab> <tab > <a href="https://web.dev/explore/devices" track-metadata-eventdetail="https://web.dev/explore/devices" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - devices" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Devices" track-name="devices" > Devices </a> </tab> <tab > <a href="https://web.dev/explore/animations" track-metadata-eventdetail="https://web.dev/explore/animations" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - animations" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Animations" track-name="animations" > Animations </a> </tab> <tab > <a href="https://web.dev/explore/identity" track-metadata-eventdetail="https://web.dev/explore/identity" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - identity" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Identity" track-name="identity" > Identity </a> </tab> <tab > <a href="https://web.dev/explore/webassembly" track-metadata-eventdetail="https://web.dev/explore/webassembly" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - webassembly" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: WebAssembly" track-name="webassembly" > WebAssembly </a> </tab> <tab > <a href="https://web.dev/explore/test-automation" track-metadata-eventdetail="https://web.dev/explore/test-automation" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - test automation" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Test automation" track-name="test automation" > Test automation </a> </tab> <tab > <a href="https://web.dev/explore/react" track-metadata-eventdetail="https://web.dev/explore/react" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - react" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: React" track-name="react" > React </a> </tab> <tab > <a href="https://web.dev/explore/angular" track-metadata-eventdetail="https://web.dev/explore/angular" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - angular" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Angular" track-name="angular" > Angular </a> </tab> <tab > <a href="https://web.dev/explore/mini-apps" track-metadata-eventdetail="https://web.dev/explore/mini-apps" class="devsite-tabs-content gc-analytics-event " track-type="nav" track-metadata-position="nav - mini apps" track-metadata-module="primary nav" data-category="Site-Wide Custom Events" data-label="Tab: Mini apps" track-name="mini apps" > Mini apps </a> </tab> </nav> </devsite-tabs> </div> </div> </div> </div> </devsite-header> <devsite-book-nav scrollbars > <div class="devsite-book-nav-filter" hidden> <span class="filter-list-icon material-icons" aria-hidden="true"></span> <input type="text" placeholder="Filter" aria-label="Type to filter" role="searchbox"> <span class="filter-clear-button hidden" data-title="Clear filter" aria-label="Clear filter" role="button" tabindex="0"></span> </div> <nav class="devsite-book-nav devsite-nav nocontent" aria-label="Side menu"> <div class="devsite-mobile-header"> <button type="button" id="devsite-close-nav" class="devsite-header-icon-button button-flat material-icons gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Close navigation" aria-label="Close navigation"> </button> <div class="devsite-product-name-wrapper"> <a href="/" class="devsite-site-logo-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Site logo" track-type="globalNav" track-name="webDev" track-metadata-position="nav" track-metadata-eventDetail="nav"> <picture> <source srcset="https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625/web/images/lockup-dark-theme.svg" media="(prefers-color-scheme: dark)" class="devsite-dark-theme" alt="web.dev"> <img src="https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625/web/images/lockup.svg" class="devsite-site-logo" alt="web.dev"> </picture> </a> <span class="devsite-product-name"> <ul class="devsite-breadcrumb-list" > <li class="devsite-breadcrumb-item "> </li> </ul> </span> </div> </div> <div class="devsite-book-nav-wrapper"> <div class="devsite-mobile-nav-top"> <ul class="devsite-nav-list"> <li class="devsite-nav-item"> <a href="/about" class="devsite-nav-title gc-analytics-event " data-category="Site-Wide Custom Events" data-label="Tab: About" track-name="about" data-category="Site-Wide Custom Events" data-label="Responsive Tab: About" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > About </span> </a> </li> <li class="devsite-nav-item"> <a href="/html" class="devsite-nav-title gc-analytics-event " data-category="Site-Wide Custom Events" data-label="Tab: HTML" track-name="html" data-category="Site-Wide Custom Events" data-label="Responsive Tab: HTML" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > HTML </span> </a> </li> <li class="devsite-nav-item"> <a href="/css" class="devsite-nav-title gc-analytics-event " data-category="Site-Wide Custom Events" data-label="Tab: CSS" track-name="css" data-category="Site-Wide Custom Events" data-label="Responsive Tab: CSS" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > CSS </span> </a> </li> <li class="devsite-nav-item"> <a href="/javascript" class="devsite-nav-title gc-analytics-event " data-category="Site-Wide Custom Events" data-label="Tab: JavaScript" track-name="javascript" data-category="Site-Wide Custom Events" data-label="Responsive Tab: JavaScript" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > JavaScript </span> </a> </li> <li class="devsite-nav-item"> <a href="/blog" class="devsite-nav-title gc-analytics-event " data-category="Site-Wide Custom Events" data-label="Tab: Blog" track-name="blog" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Blog" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Blog </span> </a> </li> <li class="devsite-nav-item"> <a href="/learn" class="devsite-nav-title gc-analytics-event " data-category="Site-Wide Custom Events" data-label="Tab: Learn" track-name="learn" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Learn" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Learn </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore" class="devsite-nav-title gc-analytics-event devsite-nav-active" data-category="Site-Wide Custom Events" data-label="Tab: Explore" track-name="explore" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Explore" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Explore </span> </a> <ul class="devsite-nav-responsive-tabs"> <li class="devsite-nav-item"> <a href="/explore/learn-core-web-vitals" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Core Web Vitals" track-name="core web vitals" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Core Web Vitals" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Core Web Vitals </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/metrics" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Metrics" track-name="metrics" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Metrics" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Metrics </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/fast" class="devsite-nav-title gc-analytics-event devsite-nav-has-children devsite-nav-active" data-category="Site-Wide Custom Events" data-label="Tab: Fast load times" track-name="fast load times" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Fast load times" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip menu="_book"> Fast load times </span> <span class="devsite-nav-icon material-icons" data-icon="forward" menu="_book"> </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/ai" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: AI" track-name="ai" data-category="Site-Wide Custom Events" data-label="Responsive Tab: AI" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > AI </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/how-to-optimize-inp" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Optimize Interaction to Next Paint (INP)" track-name="optimize interaction to next paint (inp)" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Optimize Interaction to Next Paint (INP)" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Optimize Interaction to Next Paint (INP) </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/progressive-web-apps" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Progressive Web Apps" track-name="progressive web apps" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Progressive Web Apps" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Progressive Web Apps </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/accessibility" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Accessible to all" track-name="accessible to all" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Accessible to all" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Accessible to all </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/reliable" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Network reliability" track-name="network reliability" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Network reliability" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Network reliability </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/secure" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Safe and secure" track-name="safe and secure" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Safe and secure" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Safe and secure </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/discoverable" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Easily discoverable" track-name="easily discoverable" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Easily discoverable" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Easily discoverable </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/payments" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Web Payments" track-name="web payments" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Web Payments" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Web Payments </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/media" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Media" track-name="media" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Media" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Media </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/devices" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Devices" track-name="devices" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Devices" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Devices </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/animations" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Animations" track-name="animations" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Animations" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Animations </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/identity" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Identity" track-name="identity" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Identity" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Identity </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/webassembly" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: WebAssembly" track-name="webassembly" data-category="Site-Wide Custom Events" data-label="Responsive Tab: WebAssembly" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > WebAssembly </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/test-automation" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Test automation" track-name="test automation" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Test automation" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Test automation </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/react" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: React" track-name="react" data-category="Site-Wide Custom Events" data-label="Responsive Tab: React" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > React </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/angular" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Angular" track-name="angular" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Angular" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Angular </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> <li class="devsite-nav-item"> <a href="/explore/mini-apps" class="devsite-nav-title gc-analytics-event devsite-nav-has-children " data-category="Site-Wide Custom Events" data-label="Tab: Mini apps" track-name="mini apps" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Mini apps" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Mini apps </span> <span class="devsite-nav-icon material-icons" data-icon="forward" > </span> </a> </li> </ul> </li> <li class="devsite-nav-item"> <a href="/patterns" class="devsite-nav-title gc-analytics-event " data-category="Site-Wide Custom Events" data-label="Tab: Patterns" track-name="patterns" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Patterns" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Patterns </span> </a> </li> <li class="devsite-nav-item"> <a href="/case-studies" class="devsite-nav-title gc-analytics-event " data-category="Site-Wide Custom Events" data-label="Tab: Case studies" track-name="case studies" data-category="Site-Wide Custom Events" data-label="Responsive Tab: Case studies" track-type="globalNav" track-metadata-eventDetail="globalMenu" track-metadata-position="nav"> <span class="devsite-nav-text" tooltip > Case studies </span> </a> </li> </ul> </div> <div class="devsite-mobile-nav-bottom"> <ul class="devsite-nav-list" menu="_book"> <li class="devsite-nav-item devsite-nav-heading"><div class="devsite-nav-title devsite-nav-title-no-path"> <span class="devsite-nav-text" tooltip>Introduction</span> </div></li> <li class="devsite-nav-item"><a href="/articles/why-speed-matters" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/why-speed-matters" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/why-speed-matters" ><span class="devsite-nav-text" tooltip>Why does speed matter?</span></a></li> <li class="devsite-nav-item"><a href="/articles/what-is-speed" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/what-is-speed" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/what-is-speed" ><span class="devsite-nav-text" tooltip>What is speed?</span></a></li> <li class="devsite-nav-item"><a href="/articles/how-to-measure-speed" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/how-to-measure-speed" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/how-to-measure-speed" ><span class="devsite-nav-text" tooltip>How to measure speed?</span></a></li> <li class="devsite-nav-item"><a href="/articles/how-to-stay-fast" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/how-to-stay-fast" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/how-to-stay-fast" ><span class="devsite-nav-text" tooltip>How to stay fast?</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>Core Web Vitals</span> </div></li> <li class="devsite-nav-item"><a href="/articles/vitals" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/vitals" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/vitals" ><span class="devsite-nav-text" tooltip>Web Vitals</span></a></li> <li class="devsite-nav-item"><a href="/articles/user-centric-performance-metrics" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/user-centric-performance-metrics" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/user-centric-performance-metrics" ><span class="devsite-nav-text" tooltip>User-centric performance metrics</span></a></li> <li class="devsite-nav-item"><a href="/articles/defining-core-web-vitals-thresholds" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/defining-core-web-vitals-thresholds" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/defining-core-web-vitals-thresholds" ><span class="devsite-nav-text" tooltip>Defining the Core Web Vitals metrics thresholds</span></a></li> <li class="devsite-nav-item"><a href="/articles/lcp" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/lcp" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/lcp" ><span class="devsite-nav-text" tooltip>Largest Contentful Paint (LCP)</span></a></li> <li class="devsite-nav-item"><a href="/articles/cls" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/cls" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/cls" ><span class="devsite-nav-text" tooltip>Cumulative Layout Shift (CLS)</span></a></li> <li class="devsite-nav-item"><a href="/articles/inp" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/inp" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/inp" ><span class="devsite-nav-text" tooltip>Interaction to Next Paint (INP)</span></a></li> <li class="devsite-nav-item"><a href="/articles/optimize-lcp" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/optimize-lcp" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/optimize-lcp" ><span class="devsite-nav-text" tooltip>Optimize Largest Contentful Paint</span></a></li> <li class="devsite-nav-item"><a href="/articles/optimize-cls" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/optimize-cls" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/optimize-cls" ><span class="devsite-nav-text" tooltip>Optimize Cumulative Layout Shift</span></a></li> <li class="devsite-nav-item"><a href="/articles/optimize-inp" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/optimize-inp" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/optimize-inp" ><span class="devsite-nav-text" tooltip>Optimize Interaction to Next Paint</span></a></li> <li class="devsite-nav-item"><a href="/articles/top-cwv" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/top-cwv" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/top-cwv" ><span class="devsite-nav-text" tooltip>The most effective ways to improve Core Web Vitals</span></a></li> <li class="devsite-nav-item"><a href="/articles/vitals-tools" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/vitals-tools" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/vitals-tools" ><span class="devsite-nav-text" tooltip>Core Web Vitals workflows with Google tools</span></a></li> <li class="devsite-nav-item"><a href="/articles/optimize-cwv-business" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/optimize-cwv-business" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/optimize-cwv-business" ><span class="devsite-nav-text" tooltip>Optimizing Core Web Vitals for business decision makers</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>Measure performance in the field</span> </div></li> <li class="devsite-nav-item"><a href="/articles/chrome-ux-report" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/chrome-ux-report" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/chrome-ux-report" ><span class="devsite-nav-text" tooltip>Using the Chrome UX Report to look at performance in the field</span></a></li> <li class="devsite-nav-item"><a href="/articles/lab-and-field-data-differences" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/lab-and-field-data-differences" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/lab-and-field-data-differences" ><span class="devsite-nav-text" tooltip>Why lab and field data can be different (and what to do about it)</span></a></li> <li class="devsite-nav-item"><a href="/articles/crux-and-rum-differences" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/crux-and-rum-differences" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/crux-and-rum-differences" ><span class="devsite-nav-text" tooltip>Why is CrUX data different from my RUM data?</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>Optimize your resource delivery</span> </div></li> <li class="devsite-nav-item"><a href="/articles/optimize-ttfb" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/optimize-ttfb" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/optimize-ttfb" ><span class="devsite-nav-text" tooltip>Optimize Time to First Byte</span></a></li> <li class="devsite-nav-item"><a href="/articles/content-delivery-networks" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/content-delivery-networks" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/content-delivery-networks" ><span class="devsite-nav-text" tooltip>Content delivery networks (CDNs)</span></a></li> <li class="devsite-nav-item"><a href="/articles/prioritize-resources" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/prioritize-resources" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/prioritize-resources" ><span class="devsite-nav-text" tooltip>Prioritize resources</span></a></li> <li class="devsite-nav-item"><a href="/articles/preload-critical-assets" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/preload-critical-assets" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/preload-critical-assets" ><span class="devsite-nav-text" tooltip>Preload critical assets to improve loading speed</span></a></li> <li class="devsite-nav-item"><a href="/articles/preconnect-and-dns-prefetch" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/preconnect-and-dns-prefetch" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/preconnect-and-dns-prefetch" ><span class="devsite-nav-text" tooltip>Establish network connections early to improve perceived page speed</span></a></li> <li class="devsite-nav-item"><a href="/articles/link-prefetch" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/link-prefetch" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/link-prefetch" ><span class="devsite-nav-text" tooltip>Prefetch resources to speed up future navigations</span></a></li> <li class="devsite-nav-item"><a href="/articles/fast-playback-with-preload" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/fast-playback-with-preload" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/fast-playback-with-preload" ><span class="devsite-nav-text" tooltip>Fast playback with audio and video preload</span></a></li> <li class="devsite-nav-item"><a href="/articles/adaptive-serving-based-on-network-quality" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/adaptive-serving-based-on-network-quality" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/adaptive-serving-based-on-network-quality" ><span class="devsite-nav-text" tooltip>Adaptive serving based on network quality</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>Optimize your images</span> </div></li> <li class="devsite-nav-item"><a href="/articles/choose-the-right-image-format" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/choose-the-right-image-format" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/choose-the-right-image-format" ><span class="devsite-nav-text" tooltip>Choose the right image format</span></a></li> <li class="devsite-nav-item"><a href="/articles/compress-images" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/compress-images" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/compress-images" ><span class="devsite-nav-text" tooltip>Choose the correct level of compression</span></a></li> <li class="devsite-nav-item"><a href="/articles/use-imagemin-to-compress-images" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/use-imagemin-to-compress-images" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/use-imagemin-to-compress-images" ><span class="devsite-nav-text" tooltip>Use Imagemin to compress images</span></a></li> <li class="devsite-nav-item"><a href="/articles/replace-gifs-with-videos" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/replace-gifs-with-videos" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/replace-gifs-with-videos" ><span class="devsite-nav-text" tooltip>Replace animated GIFs with video for faster page loads</span></a></li> <li class="devsite-nav-item"><a href="/articles/serve-responsive-images" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/serve-responsive-images" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/serve-responsive-images" ><span class="devsite-nav-text" tooltip>Serve responsive images</span></a></li> <li class="devsite-nav-item"><a href="/articles/serve-images-with-correct-dimensions" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/serve-images-with-correct-dimensions" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/serve-images-with-correct-dimensions" ><span class="devsite-nav-text" tooltip>Serve images with correct dimensions</span></a></li> <li class="devsite-nav-item"><a href="/articles/serve-images-webp" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/serve-images-webp" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/serve-images-webp" ><span class="devsite-nav-text" tooltip>Use WebP images</span></a></li> <li class="devsite-nav-item"><a href="/articles/image-cdns" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/image-cdns" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/image-cdns" ><span class="devsite-nav-text" tooltip>Use image CDNs to optimize images</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>Lazy-load images and video</span> </div></li> <li class="devsite-nav-item"><a href="/articles/browser-level-image-lazy-loading" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/browser-level-image-lazy-loading" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/browser-level-image-lazy-loading" ><span class="devsite-nav-text" tooltip>Browser-level image lazy loading for the web</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>Optimize web fonts</span> </div></li> <li class="devsite-nav-item"><a href="/articles/font-best-practices" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/font-best-practices" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/font-best-practices" ><span class="devsite-nav-text" tooltip>Best practices for fonts</span></a></li> <li class="devsite-nav-item"><a href="/articles/avoid-invisible-text" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/avoid-invisible-text" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/avoid-invisible-text" ><span class="devsite-nav-text" tooltip>Avoid invisible text during font loading</span></a></li> <li class="devsite-nav-item"><a href="/articles/optimize-webfont-loading" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/optimize-webfont-loading" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/optimize-webfont-loading" ><span class="devsite-nav-text" tooltip>Optimize web font loading and rendering</span></a></li> <li class="devsite-nav-item"><a href="/articles/reduce-webfont-size" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/reduce-webfont-size" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/reduce-webfont-size" ><span class="devsite-nav-text" tooltip>Reduce web font size</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>Optimize your CSS</span> </div></li> <li class="devsite-nav-item"><a href="/articles/defer-non-critical-css" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/defer-non-critical-css" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/defer-non-critical-css" ><span class="devsite-nav-text" tooltip>Defer non-critical CSS</span></a></li> <li class="devsite-nav-item"><a href="/articles/minify-css" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/minify-css" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/minify-css" ><span class="devsite-nav-text" tooltip>Minify CSS</span></a></li> <li class="devsite-nav-item"><a href="/articles/extract-critical-css" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/extract-critical-css" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/extract-critical-css" ><span class="devsite-nav-text" tooltip>Extract critical CSS</span></a></li> <li class="devsite-nav-item"><a href="/articles/optimize-css-background-images-with-media-queries" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/optimize-css-background-images-with-media-queries" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/optimize-css-background-images-with-media-queries" ><span class="devsite-nav-text" tooltip>Optimize CSS background images with media queries</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>Optimize your third-party resources</span> </div></li> <li class="devsite-nav-item"><a href="/articles/third-party-javascript" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/third-party-javascript" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/third-party-javascript" ><span class="devsite-nav-text" tooltip>Third-party JavaScript performance</span></a></li> <li class="devsite-nav-item"><a href="/articles/identify-slow-third-party-javascript" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/identify-slow-third-party-javascript" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/identify-slow-third-party-javascript" ><span class="devsite-nav-text" tooltip>Identify slow third-party JavaScript</span></a></li> <li class="devsite-nav-item"><a href="/articles/efficiently-load-third-party-javascript" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/efficiently-load-third-party-javascript" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/efficiently-load-third-party-javascript" ><span class="devsite-nav-text" tooltip>Efficiently load third-party JavaScript</span></a></li> <li class="devsite-nav-item"><a href="/articles/tag-best-practices" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/tag-best-practices" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/tag-best-practices" ><span class="devsite-nav-text" tooltip>Best practices for tags and tag managers</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>Optimize your JavaScript</span> </div></li> <li class="devsite-nav-item"><a href="/articles/optimize-long-tasks" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/optimize-long-tasks" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/optimize-long-tasks" ><span class="devsite-nav-text" tooltip>Optimize long tasks</span></a></li> <li class="devsite-nav-item"><a href="/articles/optimize-inp" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/optimize-inp" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/optimize-inp" ><span class="devsite-nav-text" tooltip>Optimize Interaction to Next Paint</span></a></li> <li class="devsite-nav-item"><a href="/articles/apply-instant-loading-with-prpl" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/apply-instant-loading-with-prpl" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/apply-instant-loading-with-prpl" ><span class="devsite-nav-text" tooltip>Apply instant loading with the PRPL pattern</span></a></li> <li class="devsite-nav-item"><a href="/articles/reduce-javascript-payloads-with-code-splitting" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/reduce-javascript-payloads-with-code-splitting" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/reduce-javascript-payloads-with-code-splitting" ><span class="devsite-nav-text" tooltip>Reduce JavaScript payloads with code splitting</span></a></li> <li class="devsite-nav-item"><a href="/articles/remove-unused-code" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/remove-unused-code" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/remove-unused-code" ><span class="devsite-nav-text" tooltip>Remove unused code</span></a></li> <li class="devsite-nav-item"><a href="/articles/reduce-network-payloads-using-text-compression" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/reduce-network-payloads-using-text-compression" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/reduce-network-payloads-using-text-compression" ><span class="devsite-nav-text" tooltip>Minify and compress network payloads</span></a></li> <li class="devsite-nav-item"><a href="/articles/serve-modern-code-to-modern-browsers" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/serve-modern-code-to-modern-browsers" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/serve-modern-code-to-modern-browsers" ><span class="devsite-nav-text" tooltip>Serve modern code to modern browsers for faster page loads</span></a></li> <li class="devsite-nav-item"><a href="/articles/publish-modern-javascript" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/publish-modern-javascript" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/publish-modern-javascript" ><span class="devsite-nav-text" tooltip>Publish, ship, and install modern JavaScript for faster applications</span></a></li> <li class="devsite-nav-item"><a href="/articles/commonjs-larger-bundles" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/commonjs-larger-bundles" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/commonjs-larger-bundles" ><span class="devsite-nav-text" tooltip>How CommonJS is making your bundles larger</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>Build a performance culture</span> </div></li> <li class="devsite-nav-item"><a href="/articles/value-of-speed" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/value-of-speed" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/value-of-speed" ><span class="devsite-nav-text" tooltip>The value of speed</span></a></li> <li class="devsite-nav-item"><a href="/articles/how-can-performance-improve-conversion" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/how-can-performance-improve-conversion" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/how-can-performance-improve-conversion" ><span class="devsite-nav-text" tooltip>How can performance improve conversion?</span></a></li> <li class="devsite-nav-item"><a href="/articles/what-should-you-measure-to-improve-performance" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/what-should-you-measure-to-improve-performance" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/what-should-you-measure-to-improve-performance" ><span class="devsite-nav-text" tooltip>What should you measure to improve performance?</span></a></li> <li class="devsite-nav-item"><a href="/articles/fixing-website-speed-cross-functionally" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/fixing-website-speed-cross-functionally" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/fixing-website-speed-cross-functionally" ><span class="devsite-nav-text" tooltip>Fixing website speed cross-functionally</span></a></li> <li class="devsite-nav-item"><a href="/articles/site-speed-and-business-metrics" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/site-speed-and-business-metrics" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/site-speed-and-business-metrics" ><span class="devsite-nav-text" tooltip>Relating site speed and business metrics</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 performance budgets</span> </div></li> <li class="devsite-nav-item"><a href="/articles/performance-budgets-101" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/performance-budgets-101" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/performance-budgets-101" ><span class="devsite-nav-text" tooltip>Performance budgets 101</span></a></li> <li class="devsite-nav-item"><a href="/articles/your-first-performance-budget" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/your-first-performance-budget" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/your-first-performance-budget" ><span class="devsite-nav-text" tooltip>Your first performance budget</span></a></li> <li class="devsite-nav-item"><a href="/articles/incorporate-performance-budgets-into-your-build-tools" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/incorporate-performance-budgets-into-your-build-tools" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/incorporate-performance-budgets-into-your-build-tools" ><span class="devsite-nav-text" tooltip>Incorporate performance budgets into your build process</span></a></li> <li class="devsite-nav-item"><a href="/articles/use-lighthouse-for-performance-budgets" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/use-lighthouse-for-performance-budgets" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/use-lighthouse-for-performance-budgets" ><span class="devsite-nav-text" tooltip>Use Lighthouse for performance budgets</span></a></li> <li class="devsite-nav-item"><a href="/articles/using-bundlesize-with-travis-ci" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/using-bundlesize-with-travis-ci" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/using-bundlesize-with-travis-ci" ><span class="devsite-nav-text" tooltip>Using bundlesize with Travis CI</span></a></li> <li class="devsite-nav-item"><a href="/articles/using-lighthouse-bot-to-set-a-performance-budget" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/using-lighthouse-bot-to-set-a-performance-budget" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/using-lighthouse-bot-to-set-a-performance-budget" ><span class="devsite-nav-text" tooltip>Using Lighthouse Bot to set a performance budget</span></a></li> <li class="devsite-nav-item"><a href="/articles/lighthouse-ci" class="devsite-nav-title gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Book nav link, pathname: /articles/lighthouse-ci" track-type="bookNav" track-name="click" track-metadata-eventdetail="/articles/lighthouse-ci" ><span class="devsite-nav-text" tooltip>Performance monitoring with Lighthouse CI</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-sidebar > <div class="devsite-sidebar"> <div class="devsite-sidebar-content"> <devsite-toc class="devsite-nav" role="navigation" aria-label="On this page" depth="2" scrollbars ></devsite-toc> <devsite-recommendations-sidebar class="nocontent devsite-nav"> </devsite-recommendations-sidebar> </div> </div> <devsite-content> <article class="devsite-article"> <div class="devsite-article-meta nocontent" role="navigation"> <ul class="devsite-breadcrumb-list" aria-label="Breadcrumb"> <li class="devsite-breadcrumb-item "> <a href="https://web.dev/" 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="" > Home </a> </li> <li class="devsite-breadcrumb-item "> <div class="devsite-breadcrumb-guillemet material-icons" aria-hidden="true"></div> <a href="https://web.dev/articles" 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="Articles" > Articles </a> </li> <li class="devsite-breadcrumb-item "> <div class="devsite-breadcrumb-guillemet material-icons" aria-hidden="true"></div> <a href="https://web.dev/explore" 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="" > Explore </a> </li> <li class="devsite-breadcrumb-item "> <div class="devsite-breadcrumb-guillemet material-icons" aria-hidden="true"></div> <a href="https://web.dev/explore/fast" 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="" > Fast load times </a> </li> </ul> <devsite-thumb-rating position="header"> </devsite-thumb-rating> </div> <h1 class="devsite-page-title" tabindex="-1"> The most effective ways to improve Core Web Vitals </h1> <devsite-feature-tooltip ack-key="AckCollectionsBookmarkTooltipDismiss" analytics-category="Site-Wide Custom Events" analytics-action-show="Callout Profile displayed" analytics-action-close="Callout Profile dismissed" analytics-label="Create Collection Callout" class="devsite-page-bookmark-tooltip nocontent" dismiss-button="true" id="devsite-collections-dropdown" dismiss-button-text="Dismiss" close-button-text="Got it"> <devsite-bookmark></devsite-bookmark> <span slot="popout-heading"> Stay organized with collections </span> <span slot="popout-contents"> Save and categorize content based on your preferences. </span> </devsite-feature-tooltip> <div class="devsite-page-title-meta"><devsite-view-release-notes></devsite-view-release-notes></div> <devsite-toc class="devsite-nav" depth="2" devsite-toc-embedded > </devsite-toc> <div class="devsite-article-body clearfix "> <aside class="note"><b>Note:</b> This document has been adapted from a 2023 blog post to reflect the latest best practices. It will be kept up to date as our guidance evolves, with major changes noted in the <a href="#change-log">Change log</a> section.</aside> <p>Over the years, the web community has built up a wealth of web performance optimization knowledge. While any one optimization may improve performance for many sites, all of them at once can feel overwhelming and, realistically, only some of them are applicable to any given site.</p> <p>Unless web performance is your day job, it's probably not obvious which optimizations will be the most impactful for your site. You likely won't have time for all of them, so it's important to ask yourself <em>what are the most impactful optimizations you can choose to improve performance for your users?</em></p> <p>Here's the truth about performance optimizations: you can't judge them solely on their technical merits. You also need to consider the human and organizational factors that influence how likely you'll be able to implement any given optimization. Some performance improvements may be hugely impactful in theory, but in reality, few developers will have the time or resources to implement them. On the other hand there may be hugely impactful performance best practices that just about everyone is already following. This guide identifies web performance optimizations that:</p> <ul> <li>Have the largest real-world impact</li> <li>Are relevant and applicable to most sites</li> <li>Are realistic for most developers to implement</li> </ul> <p>Taken together, these are the most realistic and impactful ways you can improve your <a href="/articles/vitals">Core Web Vitals</a> metrics. If you're new to web performance—or if you're still deciding what will give you the biggest return on investment—this is the best place to start.</p> <h2 id="inp" data-text="Interaction to Next Paint (INP)" tabindex="-1">Interaction to Next Paint (INP)</h2> <p>As the newest Core Web Vital metric, <a href="/articles/inp">Interaction to Next Paint (INP)</a> has some of the biggest opportunities for improvement. However, because many fewer sites are passing the <a href="/articles/inp#good-score">threshold</a> for "good" experiences compared to its <a href="/blog/fid">deprecated predecessor</a>, you may be among the many developers learning how to optimize interaction responsiveness for the first time. Start with these must-know techniques for the most effective ways to improve INP.</p> <h3 id="inp-long-tasks" data-text="1. Yield often to break up long tasks" tabindex="-1">1. Yield often to break up long tasks</h3> <p>Tasks are any piece of discrete work the browser does, including rendering, layout, parsing, compiling, or executing scripts. When a task exceeds 50 milliseconds in duration, it becomes a <a href="/articles/optimize-long-tasks">long task</a>. Long tasks are problematic because they can block the main thread from responding quickly to user interactions.</p> <p>While you should always strive to do as little work as possible in JavaScript, you can help the main thread along by <a href="/articles/optimize-long-tasks">breaking up long tasks</a>. You can do this by <a href="/articles/optimize-long-tasks#use_asyncawait_to_create_yield_points">yielding to the main thread often</a> so that <a href="#inp-rendering">rendering updates</a> and other user interactions can happen sooner.</p> <p> <div class="wd-browser-compat"> <p>Browser Support</p> <ul> <li data-support="yes"> <img alt="Chrome: 129." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='-10 -10 276 276'%3E%3ClinearGradient id='a' x1='145' x2='34' y1='253' y2='61' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%231e8e3e'/%3E%3Cstop offset='1' stop-color='%2334a853'/%3E%3C/linearGradient%3E%3ClinearGradient id='b' x1='111' x2='222' y1='254' y2='62' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23fcc934'/%3E%3Cstop offset='1' stop-color='%23fbbc04'/%3E%3C/linearGradient%3E%3ClinearGradient id='c' x1='17' x2='239' y1='80' y2='80' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23d93025'/%3E%3Cstop offset='1' stop-color='%23ea4335'/%3E%3C/linearGradient%3E%3Ccircle cx='128' cy='128' r='64' fill='%23fff'/%3E%3Cpath fill='url(%23a)' d='M96 183a64 64 0 0 1-23-23L17 64a128 128 0 0 0 111 192l55-96a64 64 0 0 1-87 23Z'/%3E%3Cpath fill='url(%23b)' d='M192 128a64 64 0 0 1-9 32l-55 96A128 128 0 0 0 239 64H128a64 64 0 0 1 64 64Z'/%3E%3Ccircle cx='128' cy='128' r='52' fill='%231a73e8'/%3E%3Cpath fill='url(%23c)' d='M96 73a64 64 0 0 1 32-9h111a128 128 0 0 0-222 0l56 96a64 64 0 0 1 23-87Z'/%3E%3C/svg%3E" > <span aria-hidden="true"> 129 </span> </li> <li data-support="yes"> <img alt="Edge: 129." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' width='24' height='24' viewBox='0 0 27600 27600'%3E%3ClinearGradient id='A' gradientUnits='userSpaceOnUse'/%3E%3ClinearGradient id='B' x1='6870' x2='24704' y1='18705' y2='18705' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%230c59a4'/%3E%3Cstop offset='1' stop-color='%23114a8b'/%3E%3C/linearGradient%3E%3ClinearGradient id='C' x1='16272' x2='5133' y1='10968' y2='23102' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%231b9de2'/%3E%3Cstop offset='.16' stop-color='%231595df'/%3E%3Cstop offset='.67' stop-color='%230680d7'/%3E%3Cstop offset='1' stop-color='%230078d4'/%3E%3C/linearGradient%3E%3CradialGradient id='D' cx='16720' cy='18747' r='9538' xlink:href='%23A'%3E%3Cstop offset='.72' stop-opacity='0'/%3E%3Cstop offset='.95' stop-opacity='.53'/%3E%3Cstop offset='1'/%3E%3C/radialGradient%3E%3CradialGradient id='E' cx='7130' cy='19866' r='14324' gradientTransform='matrix(.14843 -.98892 .79688 .1196 -8759 25542)' xlink:href='%23A'%3E%3Cstop offset='.76' stop-opacity='0'/%3E%3Cstop offset='.95' stop-opacity='.5'/%3E%3Cstop offset='1'/%3E%3C/radialGradient%3E%3CradialGradient id='F' cx='2523' cy='4680' r='20243' gradientTransform='matrix(-.03715 .99931 -2.12836 -.07913 13579 3530)' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%2335c1f1'/%3E%3Cstop offset='.11' stop-color='%2334c1ed'/%3E%3Cstop offset='.23' stop-color='%232fc2df'/%3E%3Cstop offset='.31' stop-color='%232bc3d2'/%3E%3Cstop offset='.67' stop-color='%2336c752'/%3E%3C/radialGradient%3E%3CradialGradient id='G' cx='24247' cy='7758' r='9734' gradientTransform='matrix(.28109 .95968 -.78353 .22949 24510 -16292)' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%2366eb6e'/%3E%3Cstop offset='1' stop-color='%2366eb6e' stop-opacity='0'/%3E%3C/radialGradient%3E%3Cpath id='H' d='M24105 20053a9345 9345 0 01-1053 472 10202 10202 0 01-3590 646c-4732 0-8855-3255-8855-7432 0-1175 680-2193 1643-2729-4280 180-5380 4640-5380 7253 0 7387 6810 8137 8276 8137 791 0 1984-230 2704-456l130-44a12834 12834 0 006660-5282c220-350-168-757-535-565z'/%3E%3Cpath id='I' d='M11571 25141a7913 7913 0 01-2273-2137 8145 8145 0 01-1514-4740 8093 8093 0 013093-6395 8082 8082 0 011373-859c312-148 846-414 1554-404a3236 3236 0 012569 1297 3184 3184 0 01636 1866c0-21 2446-7960-8005-7960-4390 0-8004 4166-8004 7820 0 2319 538 4170 1212 5604a12833 12833 0 007684 6757 12795 12795 0 003908 610c1414 0 2774-233 4045-656a7575 7575 0 01-6278-803z'/%3E%3Cpath id='J' d='M16231 15886c-80 105-330 250-330 566 0 260 170 512 472 723 1438 1003 4149 868 4156 868a5954 5954 0 003027-839 6147 6147 0 001133-850 6180 6180 0 001910-4437c26-2242-796-3732-1133-4392-2120-4141-6694-6525-11668-6525-7011 0-12703 5635-12798 12620 47-3654 3679-6605 7996-6605 350 0 2346 34 4200 1007 1634 858 2490 1894 3086 2921 618 1067 728 2415 728 2952s-271 1333-780 1990z'/%3E%3Cuse fill='url(%23B)' xlink:href='%23H'/%3E%3Cuse fill='url(%23D)' opacity='.35' xlink:href='%23H'/%3E%3Cuse fill='url(%23C)' xlink:href='%23I'/%3E%3Cuse fill='url(%23E)' opacity='.4' xlink:href='%23I'/%3E%3Cuse fill='url(%23F)' xlink:href='%23J'/%3E%3Cuse fill='url(%23G)' xlink:href='%23J'/%3E%3C/svg%3E" > <span aria-hidden="true"> 129 </span> </li> <li data-support="no"> <img alt="Firefox: not supported." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 512 512'%3E%3Cdefs%3E%3CradialGradient id='ff-b' cx='428.5' cy='55.1' r='501' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23ffbd4f'/%3E%3Cstop offset='.2' stop-color='%23ffac31'/%3E%3Cstop offset='.3' stop-color='%23ff9d17'/%3E%3Cstop offset='.3' stop-color='%23ff980e'/%3E%3Cstop offset='.4' stop-color='%23ff563b'/%3E%3Cstop offset='.5' stop-color='%23ff3750'/%3E%3Cstop offset='.7' stop-color='%23f5156c'/%3E%3Cstop offset='.8' stop-color='%23eb0878'/%3E%3Cstop offset='.9' stop-color='%23e50080'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-c' cx='245.4' cy='259.9' r='501' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.3' stop-color='%23960e18'/%3E%3Cstop offset='.3' stop-color='%23b11927' stop-opacity='.7'/%3E%3Cstop offset='.4' stop-color='%23db293d' stop-opacity='.3'/%3E%3Cstop offset='.5' stop-color='%23f5334b' stop-opacity='.1'/%3E%3Cstop offset='.5' stop-color='%23ff3750' stop-opacity='0'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-d' cx='305.8' cy='-58.6' r='363' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.3' stop-color='%23ffdc3e'/%3E%3Cstop offset='.5' stop-color='%23ff9d12'/%3E%3Cstop offset='.5' stop-color='%23ff980e'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-e' cx='190' cy='390.8' r='238.6' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.3' stop-color='%233a8ee6'/%3E%3Cstop offset='.5' stop-color='%235c79f0'/%3E%3Cstop offset='.7' stop-color='%239059ff'/%3E%3Cstop offset='1' stop-color='%23c139e6'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-f' cx='252.2' cy='201.3' r='126.5' gradientTransform='matrix(1 0 0 1 -48 31)' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.2' stop-color='%239059ff' stop-opacity='0'/%3E%3Cstop offset='.3' stop-color='%238c4ff3' stop-opacity='.1'/%3E%3Cstop offset='.8' stop-color='%237716a8' stop-opacity='.5'/%3E%3Cstop offset='1' stop-color='%236e008b' stop-opacity='.6'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-g' cx='239.1' cy='34.6' r='171.6' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23ffe226'/%3E%3Cstop offset='.1' stop-color='%23ffdb27'/%3E%3Cstop offset='.3' stop-color='%23ffc82a'/%3E%3Cstop offset='.5' stop-color='%23ffa930'/%3E%3Cstop offset='.7' stop-color='%23ff7e37'/%3E%3Cstop offset='.8' stop-color='%23ff7139'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-h' cx='374' cy='-74.3' r='732.2' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.5' stop-color='%23ff980e'/%3E%3Cstop offset='.6' stop-color='%23ff5634'/%3E%3Cstop offset='.7' stop-color='%23ff3647'/%3E%3Cstop offset='.9' stop-color='%23e31587'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-i' cx='304.6' cy='7.1' r='536.4' gradientTransform='rotate(84 303 4)' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23fff44f'/%3E%3Cstop offset='.1' stop-color='%23ffe847'/%3E%3Cstop offset='.2' stop-color='%23ffc830'/%3E%3Cstop offset='.3' stop-color='%23ff980e'/%3E%3Cstop offset='.4' stop-color='%23ff8b16'/%3E%3Cstop offset='.5' stop-color='%23ff672a'/%3E%3Cstop offset='.6' stop-color='%23ff3647'/%3E%3Cstop offset='.7' stop-color='%23e31587'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-j' cx='235' cy='98.1' r='457.1' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.5' stop-color='%23ff980e'/%3E%3Cstop offset='.6' stop-color='%23ff5634'/%3E%3Cstop offset='.7' stop-color='%23ff3647'/%3E%3Cstop offset='.9' stop-color='%23e31587'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-k' cx='355.7' cy='124.9' r='500.3' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.2' stop-color='%23ffe141'/%3E%3Cstop offset='.5' stop-color='%23ffaf1e'/%3E%3Cstop offset='.6' stop-color='%23ff980e'/%3E%3C/radialGradient%3E%3ClinearGradient id='ff-a' x1='446.9' y1='76.8' x2='47.9' y2='461.8' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.1' stop-color='%23ffe847'/%3E%3Cstop offset='.2' stop-color='%23ffc830'/%3E%3Cstop offset='.4' stop-color='%23ff980e'/%3E%3Cstop offset='.4' stop-color='%23ff8b16'/%3E%3Cstop offset='.5' stop-color='%23ff672a'/%3E%3Cstop offset='.5' stop-color='%23ff3647'/%3E%3Cstop offset='.7' stop-color='%23e31587'/%3E%3C/linearGradient%3E%3ClinearGradient id='ff-l' x1='442.1' y1='74.8' x2='102.6' y2='414.3' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.2' stop-color='%23fff44f' stop-opacity='.8'/%3E%3Cstop offset='.3' stop-color='%23fff44f' stop-opacity='.6'/%3E%3Cstop offset='.5' stop-color='%23fff44f' stop-opacity='.2'/%3E%3Cstop offset='.6' stop-color='%23fff44f' stop-opacity='0'/%3E%3C/linearGradient%3E%3C/defs%3E%3Cpath d='M479 166c-11-25-32-52-49-60a249 249 0 0 1 25 73c-27-68-73-95-111-155a255 255 0 0 1-8-14 44 44 0 0 1-4-9 1 1 0 0 0 0-1 1 1 0 0 0-1 0c-60 35-81 101-83 134a120 120 0 0 0-66 25 71 71 0 0 0-6-5 111 111 0 0 1-1-58c-25 11-44 29-58 44-9-12-9-52-8-60l-8 4a175 175 0 0 0-24 21 210 210 0 0 0-22 26 203 203 0 0 0-32 73l-1 2-2 15a229 229 0 0 0-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121zM202 355l3 1-3-1zm55-145zm198-31z' fill='url(%23ff-a)'/%3E%3Cpath d='M479 166c-11-25-32-52-49-60 14 26 22 53 25 72v1a207 207 0 0 1-206 279c-113-3-212-87-231-197-3-17 0-26 2-40-2 11-3 14-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121z' fill='url(%23ff-b)'/%3E%3Cpath d='M479 166c-11-25-32-52-49-60 14 26 22 53 25 72v1a207 207 0 0 1-206 279c-113-3-212-87-231-197-3-17 0-26 2-40-2 11-3 14-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121z' fill='url(%23ff-c)'/%3E%3Cpath d='m362 195 1 1a130 130 0 0 0-22-29C266 92 322 5 331 0c-60 35-81 101-83 134l9-1c45 0 84 25 105 62z' fill='url(%23ff-d)'/%3E%3Cpath d='M257 210c-1 6-22 26-29 26-68 0-80 41-80 41 3 35 28 64 57 79l4 2 7 3a107 107 0 0 0 31 6c120 6 143-143 57-186 22-4 45 5 58 14-21-37-60-62-105-62l-9 1a120 120 0 0 0-66 25l17 16c16 16 58 33 58 35z' fill='url(%23ff-e)'/%3E%3Cpath d='M257 210c-1 6-22 26-29 26-68 0-80 41-80 41 3 35 28 64 57 79l4 2 7 3a107 107 0 0 0 31 6c120 6 143-143 57-186 22-4 45 5 58 14-21-37-60-62-105-62l-9 1a120 120 0 0 0-66 25l17 16c16 16 58 33 58 35z' fill='url(%23ff-f)'/%3E%3Cpath d='m171 151 5 3a111 111 0 0 1-1-58c-25 11-44 29-58 44 1 0 36 0 54 11z' fill='url(%23ff-g)'/%3E%3Cpath d='M18 261a242 242 0 0 0 231 197 207 207 0 0 0 206-279c8 56-20 110-64 146-86 71-169 43-186 31l-3-1c-50-24-71-70-67-110-42 0-57-35-57-35s38-28 89-4c46 22 90 4 90 4 0-2-42-19-58-35l-17-16a71 71 0 0 0-6-5l-5-3c-18-11-52-11-54-11-9-12-9-51-8-60l-8 4a175 175 0 0 0-24 21 210 210 0 0 0-22 26 203 203 0 0 0-32 73c0 1-9 38-5 57z' fill='url(%23ff-h)'/%3E%3Cpath d='M341 167a130 130 0 0 1 22 29 46 46 0 0 1 4 3c55 50 26 121 24 126 44-36 72-90 64-146-27-68-73-95-111-155a255 255 0 0 1-8-14 44 44 0 0 1-4-9 1 1 0 0 0 0-1 1 1 0 0 0-1 0c-9 5-65 92 10 167z' fill='url(%23ff-i)'/%3E%3Cpath d='M367 199a46 46 0 0 0-4-3l-1-1c-13-9-36-18-58-15 86 44 63 193-57 187a107 107 0 0 1-31-6 131 131 0 0 1-11-5c17 12 99 39 186-31 2-5 31-76-24-126z' fill='url(%23ff-j)'/%3E%3Cpath d='M148 277s12-41 80-41c7 0 28-20 29-26s-44 18-90-4c-51-24-89 4-89 4s15 35 57 35c-4 40 16 85 67 110l3 1c-29-15-54-44-57-79z' fill='url(%23ff-k)'/%3E%3Cpath d='M479 166c-11-25-32-52-49-60a249 249 0 0 1 25 73c-27-68-73-95-111-155a255 255 0 0 1-8-14 44 44 0 0 1-4-9 1 1 0 0 0 0-1 1 1 0 0 0-1 0c-60 35-81 101-83 134l9-1c45 0 84 25 105 62-13-9-36-18-58-14 86 43 63 192-57 186a107 107 0 0 1-31-6 131 131 0 0 1-11-5l-3-1 3 1c-29-15-54-44-57-79 0 0 12-41 80-41 7 0 28-20 29-26 0-2-42-19-58-35l-17-16a71 71 0 0 0-6-5 111 111 0 0 1-1-58c-25 11-44 29-58 44-9-12-9-52-8-60l-8 4a175 175 0 0 0-24 21 210 210 0 0 0-22 26 203 203 0 0 0-32 73l-1 2-2 15a279 279 0 0 0-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121zm-24 13z' fill='url(%23ff-l)'/%3E%3C/svg%3E" > <span aria-hidden="true"> x </span> </li> <li data-support="no"> <img alt="Safari: not supported." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' width='24' height='24' viewBox='195 190 135 135'%3E%3Cdefs%3E%3ClinearGradient id='s-a' x1='132.6' x2='134.4' y1='111.7' y2='-105.3' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%23d2d2d2' /%3E%3Cstop offset='.5' stop-color='%23f2f2f2' /%3E%3Cstop offset='1' stop-color='%23fff' /%3E%3C/linearGradient%3E%3ClinearGradient id='s-b' gradientUnits='userSpaceOnUse' /%3E%3ClinearGradient id='s-c' x1='65.4' x2='67.4' y1='115.7' y2='17.1' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%23005ad5' /%3E%3Cstop offset='.2' stop-color='%230875f0' /%3E%3Cstop offset='.3' stop-color='%23218cee' /%3E%3Cstop offset='.6' stop-color='%2327a5f3' /%3E%3Cstop offset='.8' stop-color='%2325aaf2' /%3E%3Cstop offset='1' stop-color='%2321aaef' /%3E%3C/linearGradient%3E%3ClinearGradient id='s-d' x1='158.7' x2='176.3' y1='96.7' y2='79.5' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%23c72e24' /%3E%3Cstop offset='1' stop-color='%23fd3b2f' /%3E%3C/linearGradient%3E%3CradialGradient id='s-i' cx='-69.9' cy='69.3' r='54' gradientTransform='matrix(.9 -.01 .04 2.72 -9 -120)' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%2324a5f3' stop-opacity='0' /%3E%3Cstop offset='1' stop-color='%231e8ceb' /%3E%3C/radialGradient%3E%3CradialGradient id='s-j' cx='109.3' cy='13.8' r='93.1' gradientTransform='matrix(-.02 1.1 -1.04 -.02 137 -115)' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-opacity='0' /%3E%3Cstop offset='1' stop-color='%235488d6' stop-opacity='0' /%3E%3Cstop offset='1' stop-color='%235d96eb' /%3E%3C/radialGradient%3E%3C/defs%3E%3Crect width='220' height='220' x='22' y='-107' fill='url(%23s-a)' ry='49' transform='matrix(.57 0 0 .57 187 256)' /%3E%3Cg transform='translate(194 190)'%3E%3Ccircle cx='67.8' cy='67.7' fill='url(%23s-c)' paint-order='stroke fill markers' r='54' /%3E%3Ccircle cx='-69.9' cy='69.3' fill='url(%23s-i)' transform='translate(138 -2)' r='54' /%3E%3C/g%3E%3Cellipse cx='120' cy='14.2' fill='url(%23s-j)' rx='93.1' ry='93.7' transform='matrix(.58 0 0 .58 192 250)' /%3E%3Cg transform='matrix(.58 0 0 .57 197 182)'%3E%3Cpath fill='%23cac7c8' d='M46 192h1l72-48-7-9-66 57Z' /%3E%3Cpath fill='%23fbfffc' d='M46 191v1l66-57-7-9-59 65Z' /%3E%3Cpath fill='url(%23s-d)' d='m119 144-7-9 66-57-59 66Z' /%3E%3Cpath fill='%23fb645c' d='m105 126 7 9 66-57-1-1-72 49Z' /%3E%3C/g%3E%3Cpath stroke='%23fff' stroke-linecap='round' stroke-miterlimit='1' stroke-width='1.3' d='m287 278 3-2m-12-17 8-2m-8-3h4m-4-13 8 2m-8 3h4m-1-13 7 3m-4-11 7 4m-2-11 6 6m0-12 6 7m1-11 4 6m4-10 3 7m5-9 2 7m15-7-1 7m10-5-3 7m11-4-4 7m11-2-5 6m16 7-7 4m10 4-7 3m10 6-8 1m8 16-8-2m5 10-7-3m4 11-7-4m2 11-6-5m0 11-5-6m-2 11-4-7m-4 11-3-8m-6 10-1-8m-16 8 2-8m-10 5 3-7m-11 4 4-7m-11 2 5-6m-8 3 3-3m4 8 2-3m5 8 2-4m6 7 1-4m8 5v-4m8 4v-4m9 3-1-4m9 1-2-4m9 0-2-4m9-2-3-3m8-4-3-2m8-5-4-2m7-6-4-1m5-8h-4m4-8h-4m3-9-4 1m1-9-4 2m-1-9-3 2m-2-9-3 3m-4-8-2 3m-5-8-2 4m-6-6-1 3m-8-5v4m-8-4v4m-9-2 1 3m-9 0 2 3m-9 1 2 3m-9 2 3 3m-8 4 3 2m-8 5 4 2m-7 6 4 1m-4 25 4-1m-2 5 7-3m-6 7 4-2m-2 6 7-4m-13-21h8m41-41v-8m0 99v-8m49-42h-8' transform='translate(-65 8)' /%3E%3C/svg%3E" > <span aria-hidden="true"> x </span> </li> </ul> <p><a href="https://developer.mozilla.org/docs/Web/API/Scheduler/yield">Source</a></p> </div> </p> <p>The <a href="/articles/optimize-long-tasks#scheduler-api">Scheduler API</a> lets you queue work using a system of priorities. Specifically, the <a href="https://developer.mozilla.org/docs/Web/API/Scheduler/yield">scheduler.yield()</a> API breaks up long tasks while ensuring that interactions can be handled without giving up their place in the task queue.</p> <p><strong>By breaking up long tasks, you're giving the browser more opportunities to fit in critical, user-blocking work.</strong></p> <aside class="objective"> <b>Read to learn more:</b> <a href="/articles/optimize-long-tasks">Optimize long tasks</a>. </aside> <h3 id="inp-unnecessary-js" data-text="2. Avoid unnecessary JavaScript" tabindex="-1">2. Avoid unnecessary JavaScript</h3> <p><a href="https://httparchive.org/reports/state-of-javascript#bytesJs">Websites are shipping more JavaScript than ever before</a>, and the trend doesn't appear to be changing. When you ship too much JavaScript, you're creating an environment where tasks are competing for the main thread's attention. This can affect your website's responsiveness, especially during that crucial startup period.</p> <p>However, this is not an unsolvable problem, and you have options:</p> <ul> <li>Use <a href="/baseline">Baseline</a> Widely available web platform features instead of redundant, JavaScript-based implementations.</li> <li>Use the <a href="https://developer.chrome.com/docs/devtools/coverage/">coverage tool</a> in Chrome DevTools to find unused code in your scripts. By reducing the size of the resources needed during startup, you can ensure that pages spend less time parsing and compiling code, which provides a smoother initial user experience.</li> <li>Use <a href="/articles/reduce-javascript-payloads-with-code-splitting">code splitting</a> to create a separate bundle for code not necessary for the initial render, but will still be used later.</li> <li>If you're using a tag manager, periodically <a href="/articles/tag-best-practices">optimize your tags</a>. Older tags with unused code can be removed to reduce your tag manager's JavaScript footprint.</li> </ul> <aside class="objective"> <b>Read to learn more:</b> <a href="/articles/remove-unused-code">Remove unused code</a>. </aside> <h3 id="inp-rendering" data-text="3. Avoid large rendering updates" tabindex="-1">3. Avoid large rendering updates</h3> <p>JavaScript execution is just one thing that affects your website's responsiveness. Rendering is a type of expensive work in its own right—and during large rendering updates, your website may respond even more slowly to user interactions.</p> <p>Optimizing rendering work isn't a straightforward process, and depends on what you're trying to achieve. Even so, here are some things you can do to ensure that rendering tasks don't become long tasks:</p> <ul> <li>Reorganize DOM reads and writes in your JavaScript code to avoid <a href="/articles/avoid-large-complex-layouts-and-layout-thrashing#avoid_forced_synchronous_layouts">forced layout</a> and <a href="/articles/avoid-large-complex-layouts-and-layout-thrashing#avoid_layout_thrashing">layout thrashing</a>.</li> <li><a href="/articles/dom-size-and-interactivity">Keep DOM sizes small</a>. DOM size and the intensity of layout work are correlated. When the renderer has to update the layout for a very large DOM, the work required to recalculate its layout can increase significantly.</li> <li><a href="/articles/content-visibility">Use CSS containment</a> to lazily render off-screen DOM contents. It's not always straightforward, but by isolating areas containing complex layouts, you can avoid unnecessary layout and rendering work.</li> </ul> <aside class="objective"> <b>Read to learn more:</b> <a href="/articles/avoid-large-complex-layouts-and-layout-thrashing">Avoid large, complex layouts and layout thrashing</a>. </aside> <h2 id="lcp" data-text="Largest Contentful Paint (LCP)" tabindex="-1">Largest Contentful Paint (LCP)</h2> <p><a href="/articles/lcp">Largest Contentful Paint (LCP)</a> is the Core Web Vital that developers tend to struggle with the most—<a href="https://httparchive.org/reports/chrome-ux-report#cruxFastLcp">40%</a> of sites in the Chrome UX Report don't meet the <a href="/articles/lcp#what_is_a_good_lcp_score">recommended LCP threshold</a> for good user experiences. The Chrome team recommends the following techniques as the most effective ways to improve LCP.</p> <h3 id="lcp-discoverability-prioritization" data-text="1. Ensure the LCP resource is discoverable from the HTML source and prioritized" tabindex="-1">1. Ensure the LCP resource is discoverable from the HTML source and prioritized</h3> <p>The Chrome team has noticed the following in regard to LCP on the web:</p> <ul> <li>Per the <a href="https://almanac.httparchive.org/en/2022/">2022 Web Almanac</a> by HTTP Archive, <a href="https://almanac.httparchive.org/en/2022/performance#fig-8">72%</a> of mobile pages have an image as their LCP element.</li> <li>An analysis of real-user data from Chrome shows that the majority of origins with poor LCP spend <a href="/blog/common-misconceptions-lcp">less than 10%</a> of their p75 LCP time <em>downloading</em> the LCP image.</li> <li>Among pages with poor LCP, loading their LCP images is delayed on the client by <a href="/blog/common-misconceptions-lcp#real_navigation_performance_data">1,290 milliseconds</a> at the 75th percentile—that's more than half of the budget for a fast experience.</li> <li>Of pages where the LCP element was an image, <a href="https://almanac.httparchive.org/en/2022/performance#lcp-static-discoverability">39% of those images</a> had source URLs that were not discoverable in the initial HTML response (such as <code translate="no" dir="ltr"><img src="..."></code> or <code translate="no" dir="ltr"><link rel="preload" href="..."></code>), which would allow <a href="/articles/preload-scanner">the browser's preload scanner</a> to discover them as soon as possible.</li> <li>According to the Web Almanac, <a href="https://almanac.httparchive.org/en/2022/performance#lcp-prioritization">only 0.03%</a> of eligible pages were taking advantage of the <code translate="no" dir="ltr">fetchpriority</code> HTML attribute to give higher priority to resources—including those that could improve a page's LCP with relatively little effort.</li> </ul> <p>These statistics are telling in that developers have a big opportunity on the table to reduce both the <a href="/articles/optimize-lcp#lcp-breakdown">resource load delay</a> and <a href="/articles/optimize-lcp#reduce-resource-load-duration">resource load duration</a> for LCP images.</p> <p> <div class="wd-browser-compat"> <p>Browser Support</p> <ul> <li data-support="yes"> <img alt="Chrome: 102." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='-10 -10 276 276'%3E%3ClinearGradient id='a' x1='145' x2='34' y1='253' y2='61' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%231e8e3e'/%3E%3Cstop offset='1' stop-color='%2334a853'/%3E%3C/linearGradient%3E%3ClinearGradient id='b' x1='111' x2='222' y1='254' y2='62' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23fcc934'/%3E%3Cstop offset='1' stop-color='%23fbbc04'/%3E%3C/linearGradient%3E%3ClinearGradient id='c' x1='17' x2='239' y1='80' y2='80' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23d93025'/%3E%3Cstop offset='1' stop-color='%23ea4335'/%3E%3C/linearGradient%3E%3Ccircle cx='128' cy='128' r='64' fill='%23fff'/%3E%3Cpath fill='url(%23a)' d='M96 183a64 64 0 0 1-23-23L17 64a128 128 0 0 0 111 192l55-96a64 64 0 0 1-87 23Z'/%3E%3Cpath fill='url(%23b)' d='M192 128a64 64 0 0 1-9 32l-55 96A128 128 0 0 0 239 64H128a64 64 0 0 1 64 64Z'/%3E%3Ccircle cx='128' cy='128' r='52' fill='%231a73e8'/%3E%3Cpath fill='url(%23c)' d='M96 73a64 64 0 0 1 32-9h111a128 128 0 0 0-222 0l56 96a64 64 0 0 1 23-87Z'/%3E%3C/svg%3E" > <span aria-hidden="true"> 102 </span> </li> <li data-support="yes"> <img alt="Edge: 102." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' width='24' height='24' viewBox='0 0 27600 27600'%3E%3ClinearGradient id='A' gradientUnits='userSpaceOnUse'/%3E%3ClinearGradient id='B' x1='6870' x2='24704' y1='18705' y2='18705' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%230c59a4'/%3E%3Cstop offset='1' stop-color='%23114a8b'/%3E%3C/linearGradient%3E%3ClinearGradient id='C' x1='16272' x2='5133' y1='10968' y2='23102' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%231b9de2'/%3E%3Cstop offset='.16' stop-color='%231595df'/%3E%3Cstop offset='.67' stop-color='%230680d7'/%3E%3Cstop offset='1' stop-color='%230078d4'/%3E%3C/linearGradient%3E%3CradialGradient id='D' cx='16720' cy='18747' r='9538' xlink:href='%23A'%3E%3Cstop offset='.72' stop-opacity='0'/%3E%3Cstop offset='.95' stop-opacity='.53'/%3E%3Cstop offset='1'/%3E%3C/radialGradient%3E%3CradialGradient id='E' cx='7130' cy='19866' r='14324' gradientTransform='matrix(.14843 -.98892 .79688 .1196 -8759 25542)' xlink:href='%23A'%3E%3Cstop offset='.76' stop-opacity='0'/%3E%3Cstop offset='.95' stop-opacity='.5'/%3E%3Cstop offset='1'/%3E%3C/radialGradient%3E%3CradialGradient id='F' cx='2523' cy='4680' r='20243' gradientTransform='matrix(-.03715 .99931 -2.12836 -.07913 13579 3530)' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%2335c1f1'/%3E%3Cstop offset='.11' stop-color='%2334c1ed'/%3E%3Cstop offset='.23' stop-color='%232fc2df'/%3E%3Cstop offset='.31' stop-color='%232bc3d2'/%3E%3Cstop offset='.67' stop-color='%2336c752'/%3E%3C/radialGradient%3E%3CradialGradient id='G' cx='24247' cy='7758' r='9734' gradientTransform='matrix(.28109 .95968 -.78353 .22949 24510 -16292)' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%2366eb6e'/%3E%3Cstop offset='1' stop-color='%2366eb6e' stop-opacity='0'/%3E%3C/radialGradient%3E%3Cpath id='H' d='M24105 20053a9345 9345 0 01-1053 472 10202 10202 0 01-3590 646c-4732 0-8855-3255-8855-7432 0-1175 680-2193 1643-2729-4280 180-5380 4640-5380 7253 0 7387 6810 8137 8276 8137 791 0 1984-230 2704-456l130-44a12834 12834 0 006660-5282c220-350-168-757-535-565z'/%3E%3Cpath id='I' d='M11571 25141a7913 7913 0 01-2273-2137 8145 8145 0 01-1514-4740 8093 8093 0 013093-6395 8082 8082 0 011373-859c312-148 846-414 1554-404a3236 3236 0 012569 1297 3184 3184 0 01636 1866c0-21 2446-7960-8005-7960-4390 0-8004 4166-8004 7820 0 2319 538 4170 1212 5604a12833 12833 0 007684 6757 12795 12795 0 003908 610c1414 0 2774-233 4045-656a7575 7575 0 01-6278-803z'/%3E%3Cpath id='J' d='M16231 15886c-80 105-330 250-330 566 0 260 170 512 472 723 1438 1003 4149 868 4156 868a5954 5954 0 003027-839 6147 6147 0 001133-850 6180 6180 0 001910-4437c26-2242-796-3732-1133-4392-2120-4141-6694-6525-11668-6525-7011 0-12703 5635-12798 12620 47-3654 3679-6605 7996-6605 350 0 2346 34 4200 1007 1634 858 2490 1894 3086 2921 618 1067 728 2415 728 2952s-271 1333-780 1990z'/%3E%3Cuse fill='url(%23B)' xlink:href='%23H'/%3E%3Cuse fill='url(%23D)' opacity='.35' xlink:href='%23H'/%3E%3Cuse fill='url(%23C)' xlink:href='%23I'/%3E%3Cuse fill='url(%23E)' opacity='.4' xlink:href='%23I'/%3E%3Cuse fill='url(%23F)' xlink:href='%23J'/%3E%3Cuse fill='url(%23G)' xlink:href='%23J'/%3E%3C/svg%3E" > <span aria-hidden="true"> 102 </span> </li> <li data-support="yes"> <img alt="Firefox: 132." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 512 512'%3E%3Cdefs%3E%3CradialGradient id='ff-b' cx='428.5' cy='55.1' r='501' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23ffbd4f'/%3E%3Cstop offset='.2' stop-color='%23ffac31'/%3E%3Cstop offset='.3' stop-color='%23ff9d17'/%3E%3Cstop offset='.3' stop-color='%23ff980e'/%3E%3Cstop offset='.4' stop-color='%23ff563b'/%3E%3Cstop offset='.5' stop-color='%23ff3750'/%3E%3Cstop offset='.7' stop-color='%23f5156c'/%3E%3Cstop offset='.8' stop-color='%23eb0878'/%3E%3Cstop offset='.9' stop-color='%23e50080'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-c' cx='245.4' cy='259.9' r='501' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.3' stop-color='%23960e18'/%3E%3Cstop offset='.3' stop-color='%23b11927' stop-opacity='.7'/%3E%3Cstop offset='.4' stop-color='%23db293d' stop-opacity='.3'/%3E%3Cstop offset='.5' stop-color='%23f5334b' stop-opacity='.1'/%3E%3Cstop offset='.5' stop-color='%23ff3750' stop-opacity='0'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-d' cx='305.8' cy='-58.6' r='363' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.3' stop-color='%23ffdc3e'/%3E%3Cstop offset='.5' stop-color='%23ff9d12'/%3E%3Cstop offset='.5' stop-color='%23ff980e'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-e' cx='190' cy='390.8' r='238.6' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.3' stop-color='%233a8ee6'/%3E%3Cstop offset='.5' stop-color='%235c79f0'/%3E%3Cstop offset='.7' stop-color='%239059ff'/%3E%3Cstop offset='1' stop-color='%23c139e6'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-f' cx='252.2' cy='201.3' r='126.5' gradientTransform='matrix(1 0 0 1 -48 31)' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.2' stop-color='%239059ff' stop-opacity='0'/%3E%3Cstop offset='.3' stop-color='%238c4ff3' stop-opacity='.1'/%3E%3Cstop offset='.8' stop-color='%237716a8' stop-opacity='.5'/%3E%3Cstop offset='1' stop-color='%236e008b' stop-opacity='.6'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-g' cx='239.1' cy='34.6' r='171.6' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23ffe226'/%3E%3Cstop offset='.1' stop-color='%23ffdb27'/%3E%3Cstop offset='.3' stop-color='%23ffc82a'/%3E%3Cstop offset='.5' stop-color='%23ffa930'/%3E%3Cstop offset='.7' stop-color='%23ff7e37'/%3E%3Cstop offset='.8' stop-color='%23ff7139'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-h' cx='374' cy='-74.3' r='732.2' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.5' stop-color='%23ff980e'/%3E%3Cstop offset='.6' stop-color='%23ff5634'/%3E%3Cstop offset='.7' stop-color='%23ff3647'/%3E%3Cstop offset='.9' stop-color='%23e31587'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-i' cx='304.6' cy='7.1' r='536.4' gradientTransform='rotate(84 303 4)' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23fff44f'/%3E%3Cstop offset='.1' stop-color='%23ffe847'/%3E%3Cstop offset='.2' stop-color='%23ffc830'/%3E%3Cstop offset='.3' stop-color='%23ff980e'/%3E%3Cstop offset='.4' stop-color='%23ff8b16'/%3E%3Cstop offset='.5' stop-color='%23ff672a'/%3E%3Cstop offset='.6' stop-color='%23ff3647'/%3E%3Cstop offset='.7' stop-color='%23e31587'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-j' cx='235' cy='98.1' r='457.1' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.5' stop-color='%23ff980e'/%3E%3Cstop offset='.6' stop-color='%23ff5634'/%3E%3Cstop offset='.7' stop-color='%23ff3647'/%3E%3Cstop offset='.9' stop-color='%23e31587'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-k' cx='355.7' cy='124.9' r='500.3' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.2' stop-color='%23ffe141'/%3E%3Cstop offset='.5' stop-color='%23ffaf1e'/%3E%3Cstop offset='.6' stop-color='%23ff980e'/%3E%3C/radialGradient%3E%3ClinearGradient id='ff-a' x1='446.9' y1='76.8' x2='47.9' y2='461.8' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.1' stop-color='%23ffe847'/%3E%3Cstop offset='.2' stop-color='%23ffc830'/%3E%3Cstop offset='.4' stop-color='%23ff980e'/%3E%3Cstop offset='.4' stop-color='%23ff8b16'/%3E%3Cstop offset='.5' stop-color='%23ff672a'/%3E%3Cstop offset='.5' stop-color='%23ff3647'/%3E%3Cstop offset='.7' stop-color='%23e31587'/%3E%3C/linearGradient%3E%3ClinearGradient id='ff-l' x1='442.1' y1='74.8' x2='102.6' y2='414.3' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.2' stop-color='%23fff44f' stop-opacity='.8'/%3E%3Cstop offset='.3' stop-color='%23fff44f' stop-opacity='.6'/%3E%3Cstop offset='.5' stop-color='%23fff44f' stop-opacity='.2'/%3E%3Cstop offset='.6' stop-color='%23fff44f' stop-opacity='0'/%3E%3C/linearGradient%3E%3C/defs%3E%3Cpath d='M479 166c-11-25-32-52-49-60a249 249 0 0 1 25 73c-27-68-73-95-111-155a255 255 0 0 1-8-14 44 44 0 0 1-4-9 1 1 0 0 0 0-1 1 1 0 0 0-1 0c-60 35-81 101-83 134a120 120 0 0 0-66 25 71 71 0 0 0-6-5 111 111 0 0 1-1-58c-25 11-44 29-58 44-9-12-9-52-8-60l-8 4a175 175 0 0 0-24 21 210 210 0 0 0-22 26 203 203 0 0 0-32 73l-1 2-2 15a229 229 0 0 0-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121zM202 355l3 1-3-1zm55-145zm198-31z' fill='url(%23ff-a)'/%3E%3Cpath d='M479 166c-11-25-32-52-49-60 14 26 22 53 25 72v1a207 207 0 0 1-206 279c-113-3-212-87-231-197-3-17 0-26 2-40-2 11-3 14-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121z' fill='url(%23ff-b)'/%3E%3Cpath d='M479 166c-11-25-32-52-49-60 14 26 22 53 25 72v1a207 207 0 0 1-206 279c-113-3-212-87-231-197-3-17 0-26 2-40-2 11-3 14-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121z' fill='url(%23ff-c)'/%3E%3Cpath d='m362 195 1 1a130 130 0 0 0-22-29C266 92 322 5 331 0c-60 35-81 101-83 134l9-1c45 0 84 25 105 62z' fill='url(%23ff-d)'/%3E%3Cpath d='M257 210c-1 6-22 26-29 26-68 0-80 41-80 41 3 35 28 64 57 79l4 2 7 3a107 107 0 0 0 31 6c120 6 143-143 57-186 22-4 45 5 58 14-21-37-60-62-105-62l-9 1a120 120 0 0 0-66 25l17 16c16 16 58 33 58 35z' fill='url(%23ff-e)'/%3E%3Cpath d='M257 210c-1 6-22 26-29 26-68 0-80 41-80 41 3 35 28 64 57 79l4 2 7 3a107 107 0 0 0 31 6c120 6 143-143 57-186 22-4 45 5 58 14-21-37-60-62-105-62l-9 1a120 120 0 0 0-66 25l17 16c16 16 58 33 58 35z' fill='url(%23ff-f)'/%3E%3Cpath d='m171 151 5 3a111 111 0 0 1-1-58c-25 11-44 29-58 44 1 0 36 0 54 11z' fill='url(%23ff-g)'/%3E%3Cpath d='M18 261a242 242 0 0 0 231 197 207 207 0 0 0 206-279c8 56-20 110-64 146-86 71-169 43-186 31l-3-1c-50-24-71-70-67-110-42 0-57-35-57-35s38-28 89-4c46 22 90 4 90 4 0-2-42-19-58-35l-17-16a71 71 0 0 0-6-5l-5-3c-18-11-52-11-54-11-9-12-9-51-8-60l-8 4a175 175 0 0 0-24 21 210 210 0 0 0-22 26 203 203 0 0 0-32 73c0 1-9 38-5 57z' fill='url(%23ff-h)'/%3E%3Cpath d='M341 167a130 130 0 0 1 22 29 46 46 0 0 1 4 3c55 50 26 121 24 126 44-36 72-90 64-146-27-68-73-95-111-155a255 255 0 0 1-8-14 44 44 0 0 1-4-9 1 1 0 0 0 0-1 1 1 0 0 0-1 0c-9 5-65 92 10 167z' fill='url(%23ff-i)'/%3E%3Cpath d='M367 199a46 46 0 0 0-4-3l-1-1c-13-9-36-18-58-15 86 44 63 193-57 187a107 107 0 0 1-31-6 131 131 0 0 1-11-5c17 12 99 39 186-31 2-5 31-76-24-126z' fill='url(%23ff-j)'/%3E%3Cpath d='M148 277s12-41 80-41c7 0 28-20 29-26s-44 18-90-4c-51-24-89 4-89 4s15 35 57 35c-4 40 16 85 67 110l3 1c-29-15-54-44-57-79z' fill='url(%23ff-k)'/%3E%3Cpath d='M479 166c-11-25-32-52-49-60a249 249 0 0 1 25 73c-27-68-73-95-111-155a255 255 0 0 1-8-14 44 44 0 0 1-4-9 1 1 0 0 0 0-1 1 1 0 0 0-1 0c-60 35-81 101-83 134l9-1c45 0 84 25 105 62-13-9-36-18-58-14 86 43 63 192-57 186a107 107 0 0 1-31-6 131 131 0 0 1-11-5l-3-1 3 1c-29-15-54-44-57-79 0 0 12-41 80-41 7 0 28-20 29-26 0-2-42-19-58-35l-17-16a71 71 0 0 0-6-5 111 111 0 0 1-1-58c-25 11-44 29-58 44-9-12-9-52-8-60l-8 4a175 175 0 0 0-24 21 210 210 0 0 0-22 26 203 203 0 0 0-32 73l-1 2-2 15a279 279 0 0 0-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121zm-24 13z' fill='url(%23ff-l)'/%3E%3C/svg%3E" > <span aria-hidden="true"> 132 </span> </li> <li data-support="yes"> <img alt="Safari: 17.2." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' width='24' height='24' viewBox='195 190 135 135'%3E%3Cdefs%3E%3ClinearGradient id='s-a' x1='132.6' x2='134.4' y1='111.7' y2='-105.3' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%23d2d2d2' /%3E%3Cstop offset='.5' stop-color='%23f2f2f2' /%3E%3Cstop offset='1' stop-color='%23fff' /%3E%3C/linearGradient%3E%3ClinearGradient id='s-b' gradientUnits='userSpaceOnUse' /%3E%3ClinearGradient id='s-c' x1='65.4' x2='67.4' y1='115.7' y2='17.1' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%23005ad5' /%3E%3Cstop offset='.2' stop-color='%230875f0' /%3E%3Cstop offset='.3' stop-color='%23218cee' /%3E%3Cstop offset='.6' stop-color='%2327a5f3' /%3E%3Cstop offset='.8' stop-color='%2325aaf2' /%3E%3Cstop offset='1' stop-color='%2321aaef' /%3E%3C/linearGradient%3E%3ClinearGradient id='s-d' x1='158.7' x2='176.3' y1='96.7' y2='79.5' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%23c72e24' /%3E%3Cstop offset='1' stop-color='%23fd3b2f' /%3E%3C/linearGradient%3E%3CradialGradient id='s-i' cx='-69.9' cy='69.3' r='54' gradientTransform='matrix(.9 -.01 .04 2.72 -9 -120)' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%2324a5f3' stop-opacity='0' /%3E%3Cstop offset='1' stop-color='%231e8ceb' /%3E%3C/radialGradient%3E%3CradialGradient id='s-j' cx='109.3' cy='13.8' r='93.1' gradientTransform='matrix(-.02 1.1 -1.04 -.02 137 -115)' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-opacity='0' /%3E%3Cstop offset='1' stop-color='%235488d6' stop-opacity='0' /%3E%3Cstop offset='1' stop-color='%235d96eb' /%3E%3C/radialGradient%3E%3C/defs%3E%3Crect width='220' height='220' x='22' y='-107' fill='url(%23s-a)' ry='49' transform='matrix(.57 0 0 .57 187 256)' /%3E%3Cg transform='translate(194 190)'%3E%3Ccircle cx='67.8' cy='67.7' fill='url(%23s-c)' paint-order='stroke fill markers' r='54' /%3E%3Ccircle cx='-69.9' cy='69.3' fill='url(%23s-i)' transform='translate(138 -2)' r='54' /%3E%3C/g%3E%3Cellipse cx='120' cy='14.2' fill='url(%23s-j)' rx='93.1' ry='93.7' transform='matrix(.58 0 0 .58 192 250)' /%3E%3Cg transform='matrix(.58 0 0 .57 197 182)'%3E%3Cpath fill='%23cac7c8' d='M46 192h1l72-48-7-9-66 57Z' /%3E%3Cpath fill='%23fbfffc' d='M46 191v1l66-57-7-9-59 65Z' /%3E%3Cpath fill='url(%23s-d)' d='m119 144-7-9 66-57-59 66Z' /%3E%3Cpath fill='%23fb645c' d='m105 126 7 9 66-57-1-1-72 49Z' /%3E%3C/g%3E%3Cpath stroke='%23fff' stroke-linecap='round' stroke-miterlimit='1' stroke-width='1.3' d='m287 278 3-2m-12-17 8-2m-8-3h4m-4-13 8 2m-8 3h4m-1-13 7 3m-4-11 7 4m-2-11 6 6m0-12 6 7m1-11 4 6m4-10 3 7m5-9 2 7m15-7-1 7m10-5-3 7m11-4-4 7m11-2-5 6m16 7-7 4m10 4-7 3m10 6-8 1m8 16-8-2m5 10-7-3m4 11-7-4m2 11-6-5m0 11-5-6m-2 11-4-7m-4 11-3-8m-6 10-1-8m-16 8 2-8m-10 5 3-7m-11 4 4-7m-11 2 5-6m-8 3 3-3m4 8 2-3m5 8 2-4m6 7 1-4m8 5v-4m8 4v-4m9 3-1-4m9 1-2-4m9 0-2-4m9-2-3-3m8-4-3-2m8-5-4-2m7-6-4-1m5-8h-4m4-8h-4m3-9-4 1m1-9-4 2m-1-9-3 2m-2-9-3 3m-4-8-2 3m-5-8-2 4m-6-6-1 3m-8-5v4m-8-4v4m-9-2 1 3m-9 0 2 3m-9 1 2 3m-9 2 3 3m-8 4 3 2m-8 5 4 2m-7 6 4 1m-4 25 4-1m-2 5 7-3m-6 7 4-2m-2 6 7-4m-13-21h8m41-41v-8m0 99v-8m49-42h-8' transform='translate(-65 8)' /%3E%3C/svg%3E" > <span aria-hidden="true"> 17.2 </span> </li> </ul> <p><a href="https://developer.mozilla.org/docs/Web/API/HTMLImageElement/fetchPriority">Source</a></p> </div> </p> <p>Where resource load delay is the problem, it's vital to remember <strong>that it may be already too late to achieve good LCP if a page needs to wait for CSS or JavaScript to be fully loaded before images can even start loading</strong>. Further, an LCP image's resource load duration can be reduced by reprioritizing it so it receives more bandwidth and thus loads more quickly using the <code translate="no" dir="ltr">fetchpriority</code> HTML attribute.</p> <p>If your LCP element is an image, the image's URL should be discoverable in the HTML response to reduce its resource load delay. Some tips to make that possible are:</p> <ul> <li><strong>Load the image using an <code translate="no" dir="ltr"><img></code> element with the <code translate="no" dir="ltr">src</code> or <code translate="no" dir="ltr">srcset</code> attribute.</strong> Do not use non-standard attributes like <code translate="no" dir="ltr">data-src</code> that require JavaScript in order to render, as that will always be slower. <a href="https://almanac.httparchive.org/en/2022/performance#lcp-lazy-loading">9%</a> of pages obscure their LCP image behind <code translate="no" dir="ltr">data-src</code>.</li> <li><strong>Prefer server-side rendering (SSR) over client-side rendering (CSR),</strong> as SSR implies that the full page markup (including the image) is present in the HTML source. CSR solutions require JavaScript to run before the image can be discovered.</li> <li><strong>If your image needs to be referenced from an external CSS or JS file, you can still include it in the HTML source using a <code translate="no" dir="ltr"><link rel="preload"></code> tag.</strong> Note that images referenced by inline styles are not discoverable by the browser's <a href="/articles/preload-scanner">preload scanner</a>, so even though they're found in the HTML source, discovery of them might still be blocked on the loading of other resources, so preloading can help in these cases.</li> </ul> <p>Further, you can shorten a resource's load duration by ensuring that the LCP resource is loaded early, and at high priority:</p> <ul> <li><strong>Add the <code translate="no" dir="ltr">fetchpriority="high"</code> attribute to the <code translate="no" dir="ltr"><img></code> or <code translate="no" dir="ltr"><link rel="preload"></code> tag of your LCP image.</strong> This increases the priority of the image resource so it can start loading sooner.</li> <li><strong>Remove the <code translate="no" dir="ltr">loading="lazy"</code> attribute from the <code translate="no" dir="ltr"><img></code> tag of your LCP image.</strong> This avoids the load delay caused by confirming that the image appears in or near the viewport.</li> <li><strong>Defer non-critical resources when possible.</strong> Moving these resources to the end of your document, <a href="/articles/browser-level-image-lazy-loading">lazy-loading images</a> or <a href="/articles/iframe-lazy-loading">iframes</a>, or loading them asynchronously using JavaScript will help clear the way for more important resources like the LCP image to load more quickly.</li> </ul> <aside class="objective"> <b>Read to learn more:</b> <a href="/articles/optimize-lcp#1_eliminate_resource_load_delay">Eliminate resource load delay</a> and <a href="/blog/common-misconceptions-lcp">Common misconceptions about how to optimize LCP</a>. </aside> <h3 id="lcp-instant" data-text="2. Aim for instant navigations" tabindex="-1">2. Aim for instant navigations</h3> <p>The ideal user experience is never having to wait for a page to load. LCP optimizations like resource discoverability and prioritization are effective at reducing how long a user waits for the LCP element to load and render—but there's a physical limit to how quickly those bytes load over the network and are rendered on a page. Well before you reach that limit, there's a prohibitively high amount of effort required to shave off just a few more milliseconds. So, in order to achieve instant navigations, we need to take a radically different approach.</p> <p>Instant navigations try to load and render the page <em>before</em> the user starts to navigate there. This way, the prerendered page can be displayed immediately with a near-zero LCP. Restorations and speculations are two ways to do this. When a user navigates back or forward to a previously visited page, it can be quickly restored from an in-memory cache, appearing exactly as the user left it. Alternatively, web applications can try to predict where a user will go next—and when correct, the next page will have already been loaded and rendered by the time the user navigates there.</p> <p>Restoring previously visited pages is made possible by the <a href="/articles/bfcache">back/forward cache (bfcache)</a>. To use it, you must ensure that your pages meet <a href="/articles/bfcache#optimize">bfcache eligibility criteria</a>. Common reasons why pages aren't eligible for the bfcache are because they're served with <a href="/articles/bfcache#minimize-no-store"><code translate="no" dir="ltr">no-store</code></a> caching directives or have <a href="/articles/bfcache#never-use-the-unload-event"><code translate="no" dir="ltr">unload</code></a> event listeners.</p> <p>Restoring fully rendered pages improves not only loading performance, but also layout stability. You can learn more about bfcache and how effective it is for improving CLS in the <a href="#cls-bfcache">Ensure pages are eligible for bfcache</a> section.</p> <p> <div class="wd-browser-compat"> <p>Browser Support</p> <ul> <li data-support="yes"> <img alt="Chrome: 109." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='-10 -10 276 276'%3E%3ClinearGradient id='a' x1='145' x2='34' y1='253' y2='61' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%231e8e3e'/%3E%3Cstop offset='1' stop-color='%2334a853'/%3E%3C/linearGradient%3E%3ClinearGradient id='b' x1='111' x2='222' y1='254' y2='62' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23fcc934'/%3E%3Cstop offset='1' stop-color='%23fbbc04'/%3E%3C/linearGradient%3E%3ClinearGradient id='c' x1='17' x2='239' y1='80' y2='80' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23d93025'/%3E%3Cstop offset='1' stop-color='%23ea4335'/%3E%3C/linearGradient%3E%3Ccircle cx='128' cy='128' r='64' fill='%23fff'/%3E%3Cpath fill='url(%23a)' d='M96 183a64 64 0 0 1-23-23L17 64a128 128 0 0 0 111 192l55-96a64 64 0 0 1-87 23Z'/%3E%3Cpath fill='url(%23b)' d='M192 128a64 64 0 0 1-9 32l-55 96A128 128 0 0 0 239 64H128a64 64 0 0 1 64 64Z'/%3E%3Ccircle cx='128' cy='128' r='52' fill='%231a73e8'/%3E%3Cpath fill='url(%23c)' d='M96 73a64 64 0 0 1 32-9h111a128 128 0 0 0-222 0l56 96a64 64 0 0 1 23-87Z'/%3E%3C/svg%3E" > <span aria-hidden="true"> 109 </span> </li> <li data-support="yes"> <img alt="Edge: 109." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' width='24' height='24' viewBox='0 0 27600 27600'%3E%3ClinearGradient id='A' gradientUnits='userSpaceOnUse'/%3E%3ClinearGradient id='B' x1='6870' x2='24704' y1='18705' y2='18705' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%230c59a4'/%3E%3Cstop offset='1' stop-color='%23114a8b'/%3E%3C/linearGradient%3E%3ClinearGradient id='C' x1='16272' x2='5133' y1='10968' y2='23102' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%231b9de2'/%3E%3Cstop offset='.16' stop-color='%231595df'/%3E%3Cstop offset='.67' stop-color='%230680d7'/%3E%3Cstop offset='1' stop-color='%230078d4'/%3E%3C/linearGradient%3E%3CradialGradient id='D' cx='16720' cy='18747' r='9538' xlink:href='%23A'%3E%3Cstop offset='.72' stop-opacity='0'/%3E%3Cstop offset='.95' stop-opacity='.53'/%3E%3Cstop offset='1'/%3E%3C/radialGradient%3E%3CradialGradient id='E' cx='7130' cy='19866' r='14324' gradientTransform='matrix(.14843 -.98892 .79688 .1196 -8759 25542)' xlink:href='%23A'%3E%3Cstop offset='.76' stop-opacity='0'/%3E%3Cstop offset='.95' stop-opacity='.5'/%3E%3Cstop offset='1'/%3E%3C/radialGradient%3E%3CradialGradient id='F' cx='2523' cy='4680' r='20243' gradientTransform='matrix(-.03715 .99931 -2.12836 -.07913 13579 3530)' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%2335c1f1'/%3E%3Cstop offset='.11' stop-color='%2334c1ed'/%3E%3Cstop offset='.23' stop-color='%232fc2df'/%3E%3Cstop offset='.31' stop-color='%232bc3d2'/%3E%3Cstop offset='.67' stop-color='%2336c752'/%3E%3C/radialGradient%3E%3CradialGradient id='G' cx='24247' cy='7758' r='9734' gradientTransform='matrix(.28109 .95968 -.78353 .22949 24510 -16292)' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%2366eb6e'/%3E%3Cstop offset='1' stop-color='%2366eb6e' stop-opacity='0'/%3E%3C/radialGradient%3E%3Cpath id='H' d='M24105 20053a9345 9345 0 01-1053 472 10202 10202 0 01-3590 646c-4732 0-8855-3255-8855-7432 0-1175 680-2193 1643-2729-4280 180-5380 4640-5380 7253 0 7387 6810 8137 8276 8137 791 0 1984-230 2704-456l130-44a12834 12834 0 006660-5282c220-350-168-757-535-565z'/%3E%3Cpath id='I' d='M11571 25141a7913 7913 0 01-2273-2137 8145 8145 0 01-1514-4740 8093 8093 0 013093-6395 8082 8082 0 011373-859c312-148 846-414 1554-404a3236 3236 0 012569 1297 3184 3184 0 01636 1866c0-21 2446-7960-8005-7960-4390 0-8004 4166-8004 7820 0 2319 538 4170 1212 5604a12833 12833 0 007684 6757 12795 12795 0 003908 610c1414 0 2774-233 4045-656a7575 7575 0 01-6278-803z'/%3E%3Cpath id='J' d='M16231 15886c-80 105-330 250-330 566 0 260 170 512 472 723 1438 1003 4149 868 4156 868a5954 5954 0 003027-839 6147 6147 0 001133-850 6180 6180 0 001910-4437c26-2242-796-3732-1133-4392-2120-4141-6694-6525-11668-6525-7011 0-12703 5635-12798 12620 47-3654 3679-6605 7996-6605 350 0 2346 34 4200 1007 1634 858 2490 1894 3086 2921 618 1067 728 2415 728 2952s-271 1333-780 1990z'/%3E%3Cuse fill='url(%23B)' xlink:href='%23H'/%3E%3Cuse fill='url(%23D)' opacity='.35' xlink:href='%23H'/%3E%3Cuse fill='url(%23C)' xlink:href='%23I'/%3E%3Cuse fill='url(%23E)' opacity='.4' xlink:href='%23I'/%3E%3Cuse fill='url(%23F)' xlink:href='%23J'/%3E%3Cuse fill='url(%23G)' xlink:href='%23J'/%3E%3C/svg%3E" > <span aria-hidden="true"> 109 </span> </li> <li data-support="no"> <img alt="Firefox: not supported." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 512 512'%3E%3Cdefs%3E%3CradialGradient id='ff-b' cx='428.5' cy='55.1' r='501' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23ffbd4f'/%3E%3Cstop offset='.2' stop-color='%23ffac31'/%3E%3Cstop offset='.3' stop-color='%23ff9d17'/%3E%3Cstop offset='.3' stop-color='%23ff980e'/%3E%3Cstop offset='.4' stop-color='%23ff563b'/%3E%3Cstop offset='.5' stop-color='%23ff3750'/%3E%3Cstop offset='.7' stop-color='%23f5156c'/%3E%3Cstop offset='.8' stop-color='%23eb0878'/%3E%3Cstop offset='.9' stop-color='%23e50080'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-c' cx='245.4' cy='259.9' r='501' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.3' stop-color='%23960e18'/%3E%3Cstop offset='.3' stop-color='%23b11927' stop-opacity='.7'/%3E%3Cstop offset='.4' stop-color='%23db293d' stop-opacity='.3'/%3E%3Cstop offset='.5' stop-color='%23f5334b' stop-opacity='.1'/%3E%3Cstop offset='.5' stop-color='%23ff3750' stop-opacity='0'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-d' cx='305.8' cy='-58.6' r='363' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.3' stop-color='%23ffdc3e'/%3E%3Cstop offset='.5' stop-color='%23ff9d12'/%3E%3Cstop offset='.5' stop-color='%23ff980e'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-e' cx='190' cy='390.8' r='238.6' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.3' stop-color='%233a8ee6'/%3E%3Cstop offset='.5' stop-color='%235c79f0'/%3E%3Cstop offset='.7' stop-color='%239059ff'/%3E%3Cstop offset='1' stop-color='%23c139e6'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-f' cx='252.2' cy='201.3' r='126.5' gradientTransform='matrix(1 0 0 1 -48 31)' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.2' stop-color='%239059ff' stop-opacity='0'/%3E%3Cstop offset='.3' stop-color='%238c4ff3' stop-opacity='.1'/%3E%3Cstop offset='.8' stop-color='%237716a8' stop-opacity='.5'/%3E%3Cstop offset='1' stop-color='%236e008b' stop-opacity='.6'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-g' cx='239.1' cy='34.6' r='171.6' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23ffe226'/%3E%3Cstop offset='.1' stop-color='%23ffdb27'/%3E%3Cstop offset='.3' stop-color='%23ffc82a'/%3E%3Cstop offset='.5' stop-color='%23ffa930'/%3E%3Cstop offset='.7' stop-color='%23ff7e37'/%3E%3Cstop offset='.8' stop-color='%23ff7139'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-h' cx='374' cy='-74.3' r='732.2' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.5' stop-color='%23ff980e'/%3E%3Cstop offset='.6' stop-color='%23ff5634'/%3E%3Cstop offset='.7' stop-color='%23ff3647'/%3E%3Cstop offset='.9' stop-color='%23e31587'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-i' cx='304.6' cy='7.1' r='536.4' gradientTransform='rotate(84 303 4)' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23fff44f'/%3E%3Cstop offset='.1' stop-color='%23ffe847'/%3E%3Cstop offset='.2' stop-color='%23ffc830'/%3E%3Cstop offset='.3' stop-color='%23ff980e'/%3E%3Cstop offset='.4' stop-color='%23ff8b16'/%3E%3Cstop offset='.5' stop-color='%23ff672a'/%3E%3Cstop offset='.6' stop-color='%23ff3647'/%3E%3Cstop offset='.7' stop-color='%23e31587'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-j' cx='235' cy='98.1' r='457.1' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.5' stop-color='%23ff980e'/%3E%3Cstop offset='.6' stop-color='%23ff5634'/%3E%3Cstop offset='.7' stop-color='%23ff3647'/%3E%3Cstop offset='.9' stop-color='%23e31587'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-k' cx='355.7' cy='124.9' r='500.3' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.2' stop-color='%23ffe141'/%3E%3Cstop offset='.5' stop-color='%23ffaf1e'/%3E%3Cstop offset='.6' stop-color='%23ff980e'/%3E%3C/radialGradient%3E%3ClinearGradient id='ff-a' x1='446.9' y1='76.8' x2='47.9' y2='461.8' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.1' stop-color='%23ffe847'/%3E%3Cstop offset='.2' stop-color='%23ffc830'/%3E%3Cstop offset='.4' stop-color='%23ff980e'/%3E%3Cstop offset='.4' stop-color='%23ff8b16'/%3E%3Cstop offset='.5' stop-color='%23ff672a'/%3E%3Cstop offset='.5' stop-color='%23ff3647'/%3E%3Cstop offset='.7' stop-color='%23e31587'/%3E%3C/linearGradient%3E%3ClinearGradient id='ff-l' x1='442.1' y1='74.8' x2='102.6' y2='414.3' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.2' stop-color='%23fff44f' stop-opacity='.8'/%3E%3Cstop offset='.3' stop-color='%23fff44f' stop-opacity='.6'/%3E%3Cstop offset='.5' stop-color='%23fff44f' stop-opacity='.2'/%3E%3Cstop offset='.6' stop-color='%23fff44f' stop-opacity='0'/%3E%3C/linearGradient%3E%3C/defs%3E%3Cpath d='M479 166c-11-25-32-52-49-60a249 249 0 0 1 25 73c-27-68-73-95-111-155a255 255 0 0 1-8-14 44 44 0 0 1-4-9 1 1 0 0 0 0-1 1 1 0 0 0-1 0c-60 35-81 101-83 134a120 120 0 0 0-66 25 71 71 0 0 0-6-5 111 111 0 0 1-1-58c-25 11-44 29-58 44-9-12-9-52-8-60l-8 4a175 175 0 0 0-24 21 210 210 0 0 0-22 26 203 203 0 0 0-32 73l-1 2-2 15a229 229 0 0 0-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121zM202 355l3 1-3-1zm55-145zm198-31z' fill='url(%23ff-a)'/%3E%3Cpath d='M479 166c-11-25-32-52-49-60 14 26 22 53 25 72v1a207 207 0 0 1-206 279c-113-3-212-87-231-197-3-17 0-26 2-40-2 11-3 14-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121z' fill='url(%23ff-b)'/%3E%3Cpath d='M479 166c-11-25-32-52-49-60 14 26 22 53 25 72v1a207 207 0 0 1-206 279c-113-3-212-87-231-197-3-17 0-26 2-40-2 11-3 14-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121z' fill='url(%23ff-c)'/%3E%3Cpath d='m362 195 1 1a130 130 0 0 0-22-29C266 92 322 5 331 0c-60 35-81 101-83 134l9-1c45 0 84 25 105 62z' fill='url(%23ff-d)'/%3E%3Cpath d='M257 210c-1 6-22 26-29 26-68 0-80 41-80 41 3 35 28 64 57 79l4 2 7 3a107 107 0 0 0 31 6c120 6 143-143 57-186 22-4 45 5 58 14-21-37-60-62-105-62l-9 1a120 120 0 0 0-66 25l17 16c16 16 58 33 58 35z' fill='url(%23ff-e)'/%3E%3Cpath d='M257 210c-1 6-22 26-29 26-68 0-80 41-80 41 3 35 28 64 57 79l4 2 7 3a107 107 0 0 0 31 6c120 6 143-143 57-186 22-4 45 5 58 14-21-37-60-62-105-62l-9 1a120 120 0 0 0-66 25l17 16c16 16 58 33 58 35z' fill='url(%23ff-f)'/%3E%3Cpath d='m171 151 5 3a111 111 0 0 1-1-58c-25 11-44 29-58 44 1 0 36 0 54 11z' fill='url(%23ff-g)'/%3E%3Cpath d='M18 261a242 242 0 0 0 231 197 207 207 0 0 0 206-279c8 56-20 110-64 146-86 71-169 43-186 31l-3-1c-50-24-71-70-67-110-42 0-57-35-57-35s38-28 89-4c46 22 90 4 90 4 0-2-42-19-58-35l-17-16a71 71 0 0 0-6-5l-5-3c-18-11-52-11-54-11-9-12-9-51-8-60l-8 4a175 175 0 0 0-24 21 210 210 0 0 0-22 26 203 203 0 0 0-32 73c0 1-9 38-5 57z' fill='url(%23ff-h)'/%3E%3Cpath d='M341 167a130 130 0 0 1 22 29 46 46 0 0 1 4 3c55 50 26 121 24 126 44-36 72-90 64-146-27-68-73-95-111-155a255 255 0 0 1-8-14 44 44 0 0 1-4-9 1 1 0 0 0 0-1 1 1 0 0 0-1 0c-9 5-65 92 10 167z' fill='url(%23ff-i)'/%3E%3Cpath d='M367 199a46 46 0 0 0-4-3l-1-1c-13-9-36-18-58-15 86 44 63 193-57 187a107 107 0 0 1-31-6 131 131 0 0 1-11-5c17 12 99 39 186-31 2-5 31-76-24-126z' fill='url(%23ff-j)'/%3E%3Cpath d='M148 277s12-41 80-41c7 0 28-20 29-26s-44 18-90-4c-51-24-89 4-89 4s15 35 57 35c-4 40 16 85 67 110l3 1c-29-15-54-44-57-79z' fill='url(%23ff-k)'/%3E%3Cpath d='M479 166c-11-25-32-52-49-60a249 249 0 0 1 25 73c-27-68-73-95-111-155a255 255 0 0 1-8-14 44 44 0 0 1-4-9 1 1 0 0 0 0-1 1 1 0 0 0-1 0c-60 35-81 101-83 134l9-1c45 0 84 25 105 62-13-9-36-18-58-14 86 43 63 192-57 186a107 107 0 0 1-31-6 131 131 0 0 1-11-5l-3-1 3 1c-29-15-54-44-57-79 0 0 12-41 80-41 7 0 28-20 29-26 0-2-42-19-58-35l-17-16a71 71 0 0 0-6-5 111 111 0 0 1-1-58c-25 11-44 29-58 44-9-12-9-52-8-60l-8 4a175 175 0 0 0-24 21 210 210 0 0 0-22 26 203 203 0 0 0-32 73l-1 2-2 15a279 279 0 0 0-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121zm-24 13z' fill='url(%23ff-l)'/%3E%3C/svg%3E" > <span aria-hidden="true"> x </span> </li> <li data-support="no"> <img alt="Safari: not supported." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' width='24' height='24' viewBox='195 190 135 135'%3E%3Cdefs%3E%3ClinearGradient id='s-a' x1='132.6' x2='134.4' y1='111.7' y2='-105.3' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%23d2d2d2' /%3E%3Cstop offset='.5' stop-color='%23f2f2f2' /%3E%3Cstop offset='1' stop-color='%23fff' /%3E%3C/linearGradient%3E%3ClinearGradient id='s-b' gradientUnits='userSpaceOnUse' /%3E%3ClinearGradient id='s-c' x1='65.4' x2='67.4' y1='115.7' y2='17.1' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%23005ad5' /%3E%3Cstop offset='.2' stop-color='%230875f0' /%3E%3Cstop offset='.3' stop-color='%23218cee' /%3E%3Cstop offset='.6' stop-color='%2327a5f3' /%3E%3Cstop offset='.8' stop-color='%2325aaf2' /%3E%3Cstop offset='1' stop-color='%2321aaef' /%3E%3C/linearGradient%3E%3ClinearGradient id='s-d' x1='158.7' x2='176.3' y1='96.7' y2='79.5' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%23c72e24' /%3E%3Cstop offset='1' stop-color='%23fd3b2f' /%3E%3C/linearGradient%3E%3CradialGradient id='s-i' cx='-69.9' cy='69.3' r='54' gradientTransform='matrix(.9 -.01 .04 2.72 -9 -120)' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%2324a5f3' stop-opacity='0' /%3E%3Cstop offset='1' stop-color='%231e8ceb' /%3E%3C/radialGradient%3E%3CradialGradient id='s-j' cx='109.3' cy='13.8' r='93.1' gradientTransform='matrix(-.02 1.1 -1.04 -.02 137 -115)' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-opacity='0' /%3E%3Cstop offset='1' stop-color='%235488d6' stop-opacity='0' /%3E%3Cstop offset='1' stop-color='%235d96eb' /%3E%3C/radialGradient%3E%3C/defs%3E%3Crect width='220' height='220' x='22' y='-107' fill='url(%23s-a)' ry='49' transform='matrix(.57 0 0 .57 187 256)' /%3E%3Cg transform='translate(194 190)'%3E%3Ccircle cx='67.8' cy='67.7' fill='url(%23s-c)' paint-order='stroke fill markers' r='54' /%3E%3Ccircle cx='-69.9' cy='69.3' fill='url(%23s-i)' transform='translate(138 -2)' r='54' /%3E%3C/g%3E%3Cellipse cx='120' cy='14.2' fill='url(%23s-j)' rx='93.1' ry='93.7' transform='matrix(.58 0 0 .58 192 250)' /%3E%3Cg transform='matrix(.58 0 0 .57 197 182)'%3E%3Cpath fill='%23cac7c8' d='M46 192h1l72-48-7-9-66 57Z' /%3E%3Cpath fill='%23fbfffc' d='M46 191v1l66-57-7-9-59 65Z' /%3E%3Cpath fill='url(%23s-d)' d='m119 144-7-9 66-57-59 66Z' /%3E%3Cpath fill='%23fb645c' d='m105 126 7 9 66-57-1-1-72 49Z' /%3E%3C/g%3E%3Cpath stroke='%23fff' stroke-linecap='round' stroke-miterlimit='1' stroke-width='1.3' d='m287 278 3-2m-12-17 8-2m-8-3h4m-4-13 8 2m-8 3h4m-1-13 7 3m-4-11 7 4m-2-11 6 6m0-12 6 7m1-11 4 6m4-10 3 7m5-9 2 7m15-7-1 7m10-5-3 7m11-4-4 7m11-2-5 6m16 7-7 4m10 4-7 3m10 6-8 1m8 16-8-2m5 10-7-3m4 11-7-4m2 11-6-5m0 11-5-6m-2 11-4-7m-4 11-3-8m-6 10-1-8m-16 8 2-8m-10 5 3-7m-11 4 4-7m-11 2 5-6m-8 3 3-3m4 8 2-3m5 8 2-4m6 7 1-4m8 5v-4m8 4v-4m9 3-1-4m9 1-2-4m9 0-2-4m9-2-3-3m8-4-3-2m8-5-4-2m7-6-4-1m5-8h-4m4-8h-4m3-9-4 1m1-9-4 2m-1-9-3 2m-2-9-3 3m-4-8-2 3m-5-8-2 4m-6-6-1 3m-8-5v4m-8-4v4m-9-2 1 3m-9 0 2 3m-9 1 2 3m-9 2 3 3m-8 4 3 2m-8 5 4 2m-7 6 4 1m-4 25 4-1m-2 5 7-3m-6 7 4-2m-2 6 7-4m-13-21h8m41-41v-8m0 99v-8m49-42h-8' transform='translate(-65 8)' /%3E%3C/svg%3E" > <span aria-hidden="true"> x </span> </li> </ul> </div> </p> <p>Prerendering the next page a user visits is another effective way to dramatically improve LCP performance, and is made possible by the <a href="https://developer.chrome.com/docs/web-platform/prerender-pages">Speculation Rules API</a>. To realize these gains, though, ensure that the correct pages are prerendered. Incorrect speculations waste resources on both the server and the client, which could hurt performance. So the less confident you are as to what the next page will be, the more conservative you should be with prerendering it. When in doubt, your analytics data can give you the confidence to more eagerly prerender pages with the highest probability of being visited next.</p> <aside class="objective"> <b>Read to learn more:</b> <a href="/articles/bfcache">Back/forward cache</a> and <a href="https://developer.chrome.com/docs/web-platform/prerender-pages">Prerender pages in Chrome for instant page navigations</a>. </aside> <h3 id="lcp-cdn" data-text="3. Use a CDN to optimize TTFB" tabindex="-1">3. Use a CDN to optimize TTFB</h3> <p>The previous recommendation focused on instant navigations, which provide the best possible experience to users, but there could be situations in which the bfcache and speculative loading techniques aren't applicable. Consider a user following a cross-origin link to your site where the initial HTML document response effectively blocks the LCP. The browser cannot start loading any subresources until it receives the first byte of the response. The sooner that happens, the sooner everything else can start happening.</p> <p>This time is known as <a href="/articles/ttfb">Time to First Byte (TTFB)</a>. The best ways to reduce TTFB are to:</p> <ul> <li>Serve your content as geographically close to your users as possible.</li> <li>Cache that content so that it can be served quickly if it's requested again in the near future.</li> </ul> <p>The best way to do both of these things is to <a href="/articles/content-delivery-networks">use a CDN</a>. CDNs distribute your resources to edge servers across the globe, thus limiting the distance those resources have to travel over the wire to users. CDNs also usually have fine-grained caching controls that can be tweaked for your site's needs.</p> <p>CDNs can also serve and cache HTML documents, but according to the Web Almanac, only <a href="https://almanac.httparchive.org/en/2022/cdn#cdn-adoption">29% of HTML document requests were served from a CDN</a>. That means there's a significant opportunity for sites to realize additional savings.</p> <p>Some tips for configuring CDNs include:</p> <ul> <li>Cache static HTML documents even for a short time. For example, is it important that content is always fresh? Or can it be a few minutes stale?</li> <li>Explore whether you can move dynamic logic running on your origin server to the <a href="https://en.wikipedia.org/wiki/Edge_computing">edge</a>, which is a feature of most modern CDNs.</li> </ul> <p>Any time you can serve content directly from the edge and avoid a trip to your origin server is a performance win. Even in cases where you <em>do</em> have to make the journey all the way to the origin, CDNs are generally optimized to do that more quickly, so it's a win either way.</p> <aside class="objective"> <b>Read to learn more:</b> <a href="/articles/optimize-ttfb">Optimize Time to First Byte</a>. </aside> <h2 id="cls" data-text="Cumulative Layout Shift (CLS)" tabindex="-1">Cumulative Layout Shift (CLS)</h2> <p><a href="/articles/cls">Cumulative Layout Shift (CLS)</a> is a measure of a web page's visual stability. While CLS is the metric most sites tend to do well on, about <a href="https://httparchive.org/reports/chrome-ux-report#cruxSmallCls">a quarter of them</a> still don't meet the <a href="/articles/cls#what_is_a_good_cls_score">recommended threshold</a>, so there remains a big opportunity for many sites to improve their user experience.</p> <h3 id="cls-sizes" data-text="1. Set explicit sizes on any content loaded from the page" tabindex="-1">1. Set explicit sizes on any content loaded from the page</h3> <p><a href="/articles/cls#layout_shifts_in_detail">Layout shifts</a> usually happen when existing content moves after other content finishes loading. The primary way to improve CLS is to reserve required space in advance as much as possible.</p> <p>The best way to fix layout shifts caused by unsized images is to <strong>explicitly set <code translate="no" dir="ltr">width</code> and <code translate="no" dir="ltr">height</code> attributes</strong> or their equivalent CSS properties. <a href="https://almanac.httparchive.org/en/2022/performance#explicit-dimensions">72%</a> of pages have at least one unsized image. Without an explicit size, these images have an initial height of <code translate="no" dir="ltr">0px</code>, which may cause layout shifts when these images load and the browser discovers their dimensions. This represents a huge opportunity for the collective web—and that opportunity requires less effort than some of the other recommendations suggested in this guide.</p> <p> <div class="wd-browser-compat"> <p>Browser Support</p> <ul> <li data-support="yes"> <img alt="Chrome: 88." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='-10 -10 276 276'%3E%3ClinearGradient id='a' x1='145' x2='34' y1='253' y2='61' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%231e8e3e'/%3E%3Cstop offset='1' stop-color='%2334a853'/%3E%3C/linearGradient%3E%3ClinearGradient id='b' x1='111' x2='222' y1='254' y2='62' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23fcc934'/%3E%3Cstop offset='1' stop-color='%23fbbc04'/%3E%3C/linearGradient%3E%3ClinearGradient id='c' x1='17' x2='239' y1='80' y2='80' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23d93025'/%3E%3Cstop offset='1' stop-color='%23ea4335'/%3E%3C/linearGradient%3E%3Ccircle cx='128' cy='128' r='64' fill='%23fff'/%3E%3Cpath fill='url(%23a)' d='M96 183a64 64 0 0 1-23-23L17 64a128 128 0 0 0 111 192l55-96a64 64 0 0 1-87 23Z'/%3E%3Cpath fill='url(%23b)' d='M192 128a64 64 0 0 1-9 32l-55 96A128 128 0 0 0 239 64H128a64 64 0 0 1 64 64Z'/%3E%3Ccircle cx='128' cy='128' r='52' fill='%231a73e8'/%3E%3Cpath fill='url(%23c)' d='M96 73a64 64 0 0 1 32-9h111a128 128 0 0 0-222 0l56 96a64 64 0 0 1 23-87Z'/%3E%3C/svg%3E" > <span aria-hidden="true"> 88 </span> </li> <li data-support="yes"> <img alt="Edge: 88." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' width='24' height='24' viewBox='0 0 27600 27600'%3E%3ClinearGradient id='A' gradientUnits='userSpaceOnUse'/%3E%3ClinearGradient id='B' x1='6870' x2='24704' y1='18705' y2='18705' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%230c59a4'/%3E%3Cstop offset='1' stop-color='%23114a8b'/%3E%3C/linearGradient%3E%3ClinearGradient id='C' x1='16272' x2='5133' y1='10968' y2='23102' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%231b9de2'/%3E%3Cstop offset='.16' stop-color='%231595df'/%3E%3Cstop offset='.67' stop-color='%230680d7'/%3E%3Cstop offset='1' stop-color='%230078d4'/%3E%3C/linearGradient%3E%3CradialGradient id='D' cx='16720' cy='18747' r='9538' xlink:href='%23A'%3E%3Cstop offset='.72' stop-opacity='0'/%3E%3Cstop offset='.95' stop-opacity='.53'/%3E%3Cstop offset='1'/%3E%3C/radialGradient%3E%3CradialGradient id='E' cx='7130' cy='19866' r='14324' gradientTransform='matrix(.14843 -.98892 .79688 .1196 -8759 25542)' xlink:href='%23A'%3E%3Cstop offset='.76' stop-opacity='0'/%3E%3Cstop offset='.95' stop-opacity='.5'/%3E%3Cstop offset='1'/%3E%3C/radialGradient%3E%3CradialGradient id='F' cx='2523' cy='4680' r='20243' gradientTransform='matrix(-.03715 .99931 -2.12836 -.07913 13579 3530)' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%2335c1f1'/%3E%3Cstop offset='.11' stop-color='%2334c1ed'/%3E%3Cstop offset='.23' stop-color='%232fc2df'/%3E%3Cstop offset='.31' stop-color='%232bc3d2'/%3E%3Cstop offset='.67' stop-color='%2336c752'/%3E%3C/radialGradient%3E%3CradialGradient id='G' cx='24247' cy='7758' r='9734' gradientTransform='matrix(.28109 .95968 -.78353 .22949 24510 -16292)' xlink:href='%23A'%3E%3Cstop offset='0' stop-color='%2366eb6e'/%3E%3Cstop offset='1' stop-color='%2366eb6e' stop-opacity='0'/%3E%3C/radialGradient%3E%3Cpath id='H' d='M24105 20053a9345 9345 0 01-1053 472 10202 10202 0 01-3590 646c-4732 0-8855-3255-8855-7432 0-1175 680-2193 1643-2729-4280 180-5380 4640-5380 7253 0 7387 6810 8137 8276 8137 791 0 1984-230 2704-456l130-44a12834 12834 0 006660-5282c220-350-168-757-535-565z'/%3E%3Cpath id='I' d='M11571 25141a7913 7913 0 01-2273-2137 8145 8145 0 01-1514-4740 8093 8093 0 013093-6395 8082 8082 0 011373-859c312-148 846-414 1554-404a3236 3236 0 012569 1297 3184 3184 0 01636 1866c0-21 2446-7960-8005-7960-4390 0-8004 4166-8004 7820 0 2319 538 4170 1212 5604a12833 12833 0 007684 6757 12795 12795 0 003908 610c1414 0 2774-233 4045-656a7575 7575 0 01-6278-803z'/%3E%3Cpath id='J' d='M16231 15886c-80 105-330 250-330 566 0 260 170 512 472 723 1438 1003 4149 868 4156 868a5954 5954 0 003027-839 6147 6147 0 001133-850 6180 6180 0 001910-4437c26-2242-796-3732-1133-4392-2120-4141-6694-6525-11668-6525-7011 0-12703 5635-12798 12620 47-3654 3679-6605 7996-6605 350 0 2346 34 4200 1007 1634 858 2490 1894 3086 2921 618 1067 728 2415 728 2952s-271 1333-780 1990z'/%3E%3Cuse fill='url(%23B)' xlink:href='%23H'/%3E%3Cuse fill='url(%23D)' opacity='.35' xlink:href='%23H'/%3E%3Cuse fill='url(%23C)' xlink:href='%23I'/%3E%3Cuse fill='url(%23E)' opacity='.4' xlink:href='%23I'/%3E%3Cuse fill='url(%23F)' xlink:href='%23J'/%3E%3Cuse fill='url(%23G)' xlink:href='%23J'/%3E%3C/svg%3E" > <span aria-hidden="true"> 88 </span> </li> <li data-support="yes"> <img alt="Firefox: 89." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 512 512'%3E%3Cdefs%3E%3CradialGradient id='ff-b' cx='428.5' cy='55.1' r='501' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23ffbd4f'/%3E%3Cstop offset='.2' stop-color='%23ffac31'/%3E%3Cstop offset='.3' stop-color='%23ff9d17'/%3E%3Cstop offset='.3' stop-color='%23ff980e'/%3E%3Cstop offset='.4' stop-color='%23ff563b'/%3E%3Cstop offset='.5' stop-color='%23ff3750'/%3E%3Cstop offset='.7' stop-color='%23f5156c'/%3E%3Cstop offset='.8' stop-color='%23eb0878'/%3E%3Cstop offset='.9' stop-color='%23e50080'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-c' cx='245.4' cy='259.9' r='501' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.3' stop-color='%23960e18'/%3E%3Cstop offset='.3' stop-color='%23b11927' stop-opacity='.7'/%3E%3Cstop offset='.4' stop-color='%23db293d' stop-opacity='.3'/%3E%3Cstop offset='.5' stop-color='%23f5334b' stop-opacity='.1'/%3E%3Cstop offset='.5' stop-color='%23ff3750' stop-opacity='0'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-d' cx='305.8' cy='-58.6' r='363' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.3' stop-color='%23ffdc3e'/%3E%3Cstop offset='.5' stop-color='%23ff9d12'/%3E%3Cstop offset='.5' stop-color='%23ff980e'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-e' cx='190' cy='390.8' r='238.6' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.3' stop-color='%233a8ee6'/%3E%3Cstop offset='.5' stop-color='%235c79f0'/%3E%3Cstop offset='.7' stop-color='%239059ff'/%3E%3Cstop offset='1' stop-color='%23c139e6'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-f' cx='252.2' cy='201.3' r='126.5' gradientTransform='matrix(1 0 0 1 -48 31)' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.2' stop-color='%239059ff' stop-opacity='0'/%3E%3Cstop offset='.3' stop-color='%238c4ff3' stop-opacity='.1'/%3E%3Cstop offset='.8' stop-color='%237716a8' stop-opacity='.5'/%3E%3Cstop offset='1' stop-color='%236e008b' stop-opacity='.6'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-g' cx='239.1' cy='34.6' r='171.6' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23ffe226'/%3E%3Cstop offset='.1' stop-color='%23ffdb27'/%3E%3Cstop offset='.3' stop-color='%23ffc82a'/%3E%3Cstop offset='.5' stop-color='%23ffa930'/%3E%3Cstop offset='.7' stop-color='%23ff7e37'/%3E%3Cstop offset='.8' stop-color='%23ff7139'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-h' cx='374' cy='-74.3' r='732.2' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.5' stop-color='%23ff980e'/%3E%3Cstop offset='.6' stop-color='%23ff5634'/%3E%3Cstop offset='.7' stop-color='%23ff3647'/%3E%3Cstop offset='.9' stop-color='%23e31587'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-i' cx='304.6' cy='7.1' r='536.4' gradientTransform='rotate(84 303 4)' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='0' stop-color='%23fff44f'/%3E%3Cstop offset='.1' stop-color='%23ffe847'/%3E%3Cstop offset='.2' stop-color='%23ffc830'/%3E%3Cstop offset='.3' stop-color='%23ff980e'/%3E%3Cstop offset='.4' stop-color='%23ff8b16'/%3E%3Cstop offset='.5' stop-color='%23ff672a'/%3E%3Cstop offset='.6' stop-color='%23ff3647'/%3E%3Cstop offset='.7' stop-color='%23e31587'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-j' cx='235' cy='98.1' r='457.1' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.5' stop-color='%23ff980e'/%3E%3Cstop offset='.6' stop-color='%23ff5634'/%3E%3Cstop offset='.7' stop-color='%23ff3647'/%3E%3Cstop offset='.9' stop-color='%23e31587'/%3E%3C/radialGradient%3E%3CradialGradient id='ff-k' cx='355.7' cy='124.9' r='500.3' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.2' stop-color='%23ffe141'/%3E%3Cstop offset='.5' stop-color='%23ffaf1e'/%3E%3Cstop offset='.6' stop-color='%23ff980e'/%3E%3C/radialGradient%3E%3ClinearGradient id='ff-a' x1='446.9' y1='76.8' x2='47.9' y2='461.8' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.1' stop-color='%23fff44f'/%3E%3Cstop offset='.1' stop-color='%23ffe847'/%3E%3Cstop offset='.2' stop-color='%23ffc830'/%3E%3Cstop offset='.4' stop-color='%23ff980e'/%3E%3Cstop offset='.4' stop-color='%23ff8b16'/%3E%3Cstop offset='.5' stop-color='%23ff672a'/%3E%3Cstop offset='.5' stop-color='%23ff3647'/%3E%3Cstop offset='.7' stop-color='%23e31587'/%3E%3C/linearGradient%3E%3ClinearGradient id='ff-l' x1='442.1' y1='74.8' x2='102.6' y2='414.3' gradientUnits='userSpaceOnUse'%3E%3Cstop offset='.2' stop-color='%23fff44f' stop-opacity='.8'/%3E%3Cstop offset='.3' stop-color='%23fff44f' stop-opacity='.6'/%3E%3Cstop offset='.5' stop-color='%23fff44f' stop-opacity='.2'/%3E%3Cstop offset='.6' stop-color='%23fff44f' stop-opacity='0'/%3E%3C/linearGradient%3E%3C/defs%3E%3Cpath d='M479 166c-11-25-32-52-49-60a249 249 0 0 1 25 73c-27-68-73-95-111-155a255 255 0 0 1-8-14 44 44 0 0 1-4-9 1 1 0 0 0 0-1 1 1 0 0 0-1 0c-60 35-81 101-83 134a120 120 0 0 0-66 25 71 71 0 0 0-6-5 111 111 0 0 1-1-58c-25 11-44 29-58 44-9-12-9-52-8-60l-8 4a175 175 0 0 0-24 21 210 210 0 0 0-22 26 203 203 0 0 0-32 73l-1 2-2 15a229 229 0 0 0-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121zM202 355l3 1-3-1zm55-145zm198-31z' fill='url(%23ff-a)'/%3E%3Cpath d='M479 166c-11-25-32-52-49-60 14 26 22 53 25 72v1a207 207 0 0 1-206 279c-113-3-212-87-231-197-3-17 0-26 2-40-2 11-3 14-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121z' fill='url(%23ff-b)'/%3E%3Cpath d='M479 166c-11-25-32-52-49-60 14 26 22 53 25 72v1a207 207 0 0 1-206 279c-113-3-212-87-231-197-3-17 0-26 2-40-2 11-3 14-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121z' fill='url(%23ff-c)'/%3E%3Cpath d='m362 195 1 1a130 130 0 0 0-22-29C266 92 322 5 331 0c-60 35-81 101-83 134l9-1c45 0 84 25 105 62z' fill='url(%23ff-d)'/%3E%3Cpath d='M257 210c-1 6-22 26-29 26-68 0-80 41-80 41 3 35 28 64 57 79l4 2 7 3a107 107 0 0 0 31 6c120 6 143-143 57-186 22-4 45 5 58 14-21-37-60-62-105-62l-9 1a120 120 0 0 0-66 25l17 16c16 16 58 33 58 35z' fill='url(%23ff-e)'/%3E%3Cpath d='M257 210c-1 6-22 26-29 26-68 0-80 41-80 41 3 35 28 64 57 79l4 2 7 3a107 107 0 0 0 31 6c120 6 143-143 57-186 22-4 45 5 58 14-21-37-60-62-105-62l-9 1a120 120 0 0 0-66 25l17 16c16 16 58 33 58 35z' fill='url(%23ff-f)'/%3E%3Cpath d='m171 151 5 3a111 111 0 0 1-1-58c-25 11-44 29-58 44 1 0 36 0 54 11z' fill='url(%23ff-g)'/%3E%3Cpath d='M18 261a242 242 0 0 0 231 197 207 207 0 0 0 206-279c8 56-20 110-64 146-86 71-169 43-186 31l-3-1c-50-24-71-70-67-110-42 0-57-35-57-35s38-28 89-4c46 22 90 4 90 4 0-2-42-19-58-35l-17-16a71 71 0 0 0-6-5l-5-3c-18-11-52-11-54-11-9-12-9-51-8-60l-8 4a175 175 0 0 0-24 21 210 210 0 0 0-22 26 203 203 0 0 0-32 73c0 1-9 38-5 57z' fill='url(%23ff-h)'/%3E%3Cpath d='M341 167a130 130 0 0 1 22 29 46 46 0 0 1 4 3c55 50 26 121 24 126 44-36 72-90 64-146-27-68-73-95-111-155a255 255 0 0 1-8-14 44 44 0 0 1-4-9 1 1 0 0 0 0-1 1 1 0 0 0-1 0c-9 5-65 92 10 167z' fill='url(%23ff-i)'/%3E%3Cpath d='M367 199a46 46 0 0 0-4-3l-1-1c-13-9-36-18-58-15 86 44 63 193-57 187a107 107 0 0 1-31-6 131 131 0 0 1-11-5c17 12 99 39 186-31 2-5 31-76-24-126z' fill='url(%23ff-j)'/%3E%3Cpath d='M148 277s12-41 80-41c7 0 28-20 29-26s-44 18-90-4c-51-24-89 4-89 4s15 35 57 35c-4 40 16 85 67 110l3 1c-29-15-54-44-57-79z' fill='url(%23ff-k)'/%3E%3Cpath d='M479 166c-11-25-32-52-49-60a249 249 0 0 1 25 73c-27-68-73-95-111-155a255 255 0 0 1-8-14 44 44 0 0 1-4-9 1 1 0 0 0 0-1 1 1 0 0 0-1 0c-60 35-81 101-83 134l9-1c45 0 84 25 105 62-13-9-36-18-58-14 86 43 63 192-57 186a107 107 0 0 1-31-6 131 131 0 0 1-11-5l-3-1 3 1c-29-15-54-44-57-79 0 0 12-41 80-41 7 0 28-20 29-26 0-2-42-19-58-35l-17-16a71 71 0 0 0-6-5 111 111 0 0 1-1-58c-25 11-44 29-58 44-9-12-9-52-8-60l-8 4a175 175 0 0 0-24 21 210 210 0 0 0-22 26 203 203 0 0 0-32 73l-1 2-2 15a279 279 0 0 0-4 34v1a240 240 0 0 0 477 40l1-9c5-41 0-84-15-121zm-24 13z' fill='url(%23ff-l)'/%3E%3C/svg%3E" > <span aria-hidden="true"> 89 </span> </li> <li data-support="yes"> <img alt="Safari: 15." src="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' width='24' height='24' viewBox='195 190 135 135'%3E%3Cdefs%3E%3ClinearGradient id='s-a' x1='132.6' x2='134.4' y1='111.7' y2='-105.3' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%23d2d2d2' /%3E%3Cstop offset='.5' stop-color='%23f2f2f2' /%3E%3Cstop offset='1' stop-color='%23fff' /%3E%3C/linearGradient%3E%3ClinearGradient id='s-b' gradientUnits='userSpaceOnUse' /%3E%3ClinearGradient id='s-c' x1='65.4' x2='67.4' y1='115.7' y2='17.1' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%23005ad5' /%3E%3Cstop offset='.2' stop-color='%230875f0' /%3E%3Cstop offset='.3' stop-color='%23218cee' /%3E%3Cstop offset='.6' stop-color='%2327a5f3' /%3E%3Cstop offset='.8' stop-color='%2325aaf2' /%3E%3Cstop offset='1' stop-color='%2321aaef' /%3E%3C/linearGradient%3E%3ClinearGradient id='s-d' x1='158.7' x2='176.3' y1='96.7' y2='79.5' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%23c72e24' /%3E%3Cstop offset='1' stop-color='%23fd3b2f' /%3E%3C/linearGradient%3E%3CradialGradient id='s-i' cx='-69.9' cy='69.3' r='54' gradientTransform='matrix(.9 -.01 .04 2.72 -9 -120)' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-color='%2324a5f3' stop-opacity='0' /%3E%3Cstop offset='1' stop-color='%231e8ceb' /%3E%3C/radialGradient%3E%3CradialGradient id='s-j' cx='109.3' cy='13.8' r='93.1' gradientTransform='matrix(-.02 1.1 -1.04 -.02 137 -115)' xlink:href='%23s-b'%3E%3Cstop offset='0' stop-opacity='0' /%3E%3Cstop offset='1' stop-color='%235488d6' stop-opacity='0' /%3E%3Cstop offset='1' stop-color='%235d96eb' /%3E%3C/radialGradient%3E%3C/defs%3E%3Crect width='220' height='220' x='22' y='-107' fill='url(%23s-a)' ry='49' transform='matrix(.57 0 0 .57 187 256)' /%3E%3Cg transform='translate(194 190)'%3E%3Ccircle cx='67.8' cy='67.7' fill='url(%23s-c)' paint-order='stroke fill markers' r='54' /%3E%3Ccircle cx='-69.9' cy='69.3' fill='url(%23s-i)' transform='translate(138 -2)' r='54' /%3E%3C/g%3E%3Cellipse cx='120' cy='14.2' fill='url(%23s-j)' rx='93.1' ry='93.7' transform='matrix(.58 0 0 .58 192 250)' /%3E%3Cg transform='matrix(.58 0 0 .57 197 182)'%3E%3Cpath fill='%23cac7c8' d='M46 192h1l72-48-7-9-66 57Z' /%3E%3Cpath fill='%23fbfffc' d='M46 191v1l66-57-7-9-59 65Z' /%3E%3Cpath fill='url(%23s-d)' d='m119 144-7-9 66-57-59 66Z' /%3E%3Cpath fill='%23fb645c' d='m105 126 7 9 66-57-1-1-72 49Z' /%3E%3C/g%3E%3Cpath stroke='%23fff' stroke-linecap='round' stroke-miterlimit='1' stroke-width='1.3' d='m287 278 3-2m-12-17 8-2m-8-3h4m-4-13 8 2m-8 3h4m-1-13 7 3m-4-11 7 4m-2-11 6 6m0-12 6 7m1-11 4 6m4-10 3 7m5-9 2 7m15-7-1 7m10-5-3 7m11-4-4 7m11-2-5 6m16 7-7 4m10 4-7 3m10 6-8 1m8 16-8-2m5 10-7-3m4 11-7-4m2 11-6-5m0 11-5-6m-2 11-4-7m-4 11-3-8m-6 10-1-8m-16 8 2-8m-10 5 3-7m-11 4 4-7m-11 2 5-6m-8 3 3-3m4 8 2-3m5 8 2-4m6 7 1-4m8 5v-4m8 4v-4m9 3-1-4m9 1-2-4m9 0-2-4m9-2-3-3m8-4-3-2m8-5-4-2m7-6-4-1m5-8h-4m4-8h-4m3-9-4 1m1-9-4 2m-1-9-3 2m-2-9-3 3m-4-8-2 3m-5-8-2 4m-6-6-1 3m-8-5v4m-8-4v4m-9-2 1 3m-9 0 2 3m-9 1 2 3m-9 2 3 3m-8 4 3 2m-8 5 4 2m-7 6 4 1m-4 25 4-1m-2 5 7-3m-6 7 4-2m-2 6 7-4m-13-21h8m41-41v-8m0 99v-8m49-42h-8' transform='translate(-65 8)' /%3E%3C/svg%3E" > <span aria-hidden="true"> 15 </span> </li> </ul> <p><a href="https://developer.mozilla.org/docs/Web/CSS/aspect-ratio">Source</a></p> </div> </p> <p>Images are not the only contributors to CLS. Layout shifts may be caused by other content that typically loads after the page initially renders, including third-party ads or embedded videos. The <a href="/articles/aspect-ratio"><code translate="no" dir="ltr">aspect-ratio</code></a> property can help here. It's a <a href="/baseline">Baseline widely available</a> CSS feature that allows developers to explicitly set an aspect ratio on images as well as non-image elements. This lets you set a dynamic <code translate="no" dir="ltr">width</code> (for example based on screen size), and have the browser automatically calculate the appropriate height, in much the same way it does for images with dimensions.</p> <p>However, it's not always possible to know the exact size of dynamic content. Even if you don't know the exact size, you can still reduce the severity of layout shifts. <strong>Setting a sensible <code translate="no" dir="ltr">min-height</code></strong> is almost always better than allowing the browser to use the default height of <code translate="no" dir="ltr">0px</code> for an empty element. Using a <code translate="no" dir="ltr">min-height</code> is also usually a straightforward fix, as it still allows the container to grow to the final content's height if needed—it has just reduced that amount of growth to a hopefully more tolerable level.</p> <aside class="objective"> <b>Read to learn more:</b> <a href="/articles/optimize-cls#images-without-dimensions">Optimize Cumulative Layout Shift</a>. </aside> <h3 id="cls-bfcache" data-text="2. Ensure pages are eligible for bfcache" tabindex="-1">2. Ensure pages are eligible for bfcache</h3> <p>As stated earlier in this guide, the <a href="/articles/bfcache">back/forward cache</a> (bfcache) instantly loads a page from earlier or later in the browser history from a memory snapshot. While the bfcache is a significant browser-level performance optimization that improves LCP, it also entirely eliminates layout shifts. In fact, <a href="https://chromium.googlesource.com/chromium/src/+/refs/heads/main/docs/speed/metrics_changelog/2022_01_bfcache.md">the introduction of the bfcache in 2022</a> was responsible for the biggest improvement in CLS that we saw that year.</p> <p>Despite this, <a href="https://almanac.httparchive.org/en/2022/performance#bfcache-eligibility">a significant number of websites</a> are ineligible for the bfcache, and so are missing out on this free web performance win. Unless your page is loading sensitive information you don't want restored from memory, ensure that your pages are eligible to use the bfcache.</p> <p>Site owners should check if pages are <a href="/articles/bfcache#optimize_your_pages_for_bfcache">eligible for the bfcache</a> and fix any reasons why they're not. Chrome <a href="/articles/bfcache#test_to_ensure_your_pages_are_cacheable">has a bfcache tester in DevTools</a> and you can also use the <a href="https://developer.chrome.com/docs/web-platform/bfcache-notrestoredreasons">Not Restored Reasons API</a> to detect ineligibility reasons in the field.</p> <aside class="objective"> <b>Read to learn more:</b> <a href="/articles/bfcache">Back/forward cache</a>. </aside> <h3 id="cls-relayout" data-text="3. Avoid animations and transitions that use layout-inducing CSS properties" tabindex="-1">3. Avoid animations and transitions that use layout-inducing CSS properties</h3> <p>Another common source of layout shifts is when elements are animated. For example, cookie banners or other notification banners that slide in from the top or bottom often contribute to CLS. This is particularly problematic when these banners push other content out of the way, but even when they don't, animating them can still impact CLS.</p> <p>While HTTP Archive data can't conclusively connect animations to layout shifts, the data does show that pages that animate any CSS property that <em>could</em> affect layout are 15% less likely to have "good" CLS than pages overall. Some properties are associated with worse CLS than others. For example, pages that animate <code translate="no" dir="ltr">margin</code> or <code translate="no" dir="ltr">border</code> widths have "poor" CLS at almost twice the rate that pages overall are assessed as poor.</p> <p>This is perhaps not surprising, because any time you transition or animate <em>any</em> layout-inducing CSS property, it will result in <a href="/articles/cls#layout_shifts_in_detail">layout shifts</a>. If those layout shifts are not within 500 milliseconds of a user interaction, they will impact CLS.</p> <p>What may be surprising to some developers is that this is true even in cases where the element is taken outside of the normal document flow. For example, absolutely positioned elements that animate <code translate="no" dir="ltr">top</code> or <code translate="no" dir="ltr">left</code> cause layout shifts, even if they aren't pushing other content around. However, if instead of animating <code translate="no" dir="ltr">top</code> or <code translate="no" dir="ltr">left</code>, you animate <code translate="no" dir="ltr">transform:translateX()</code> or <code translate="no" dir="ltr">transform:translateY()</code>, it won't cause the browser to update page layout, thus avoiding layout shifts.</p> <p>Preferring animation of CSS properties that can be updated on the browser's compositor thread has long been <a href="/articles/animations-guide">a performance best practice</a> because it moves that work off the main thread to the GPU. In addition to it being a general performance best practice, it can also help improve CLS.</p> <p>As a general rule, never animate or transition CSS properties that require the browser to update the page layout, unless you're doing it in response to a user tap or key press (though <a href="/articles/cls#user-initiated_layout_shifts">not <code translate="no" dir="ltr">hover</code></a>). Whenever possible, prefer transitions and animations using the CSS <a href="https://developer.mozilla.org/docs/Web/CSS/transform"><code translate="no" dir="ltr">transform</code></a> property.</p> <p>The <a href="https://developer.chrome.com/docs/lighthouse/performance/non-composited-animations/">Avoid non-composited animations</a> Lighthouse audit warns when a page animates potentially slow CSS properties.</p> <aside class="objective"> <b>Read to learn more:</b> <a href="/articles/optimize-cls#animation">Optimize animation-induced layout shifts</a>. </aside> <h2 id="conclusion" data-text="Conclusion" tabindex="-1">Conclusion</h2> <p>Improving page performance can seem daunting, especially given that there are mountains of guidance across the web to consider. However, by focusing on this short list of the most effective best practices, you can approach the problem with renewed focus, and hopefully move the needle for your website's Core Web Vitals.</p> <p>If you'd like to go beyond the optimizations listed here, read these guides for more information:</p> <ul> <li><a href="/articles/optimize-inp">Optimize INP</a></li> <li><a href="/articles/optimize-lcp">Optimize LCP</a></li> <li><a href="/articles/optimize-cls">Optimize CLS</a></li> </ul> <h2 id="change-log" data-text="Appendix: Change log" tabindex="-1">Appendix: Change log</h2> <p>Major changes to this document will be tracked here to help explain when and why the top recommendations have changed.</p> <h3 id="october_2024" data-text="October 2024" tabindex="-1">October 2024</h3> <p>2024 update:</p> <ul> <li>INP <ul> <li>We switched this metric from FID to INP in accordance with the launch of INP as a Core Web Vital metric and made it the top metric in the list.</li> <li>We reversed our recommendation to use the <code translate="no" dir="ltr">isInputPending</code> API as part of breaking up long tasks. You can learn more about our reasoning in the <a href="/articles/optimize-long-tasks#isinputpending">Optimize Long Tasks</a> article.</li> </ul></li> <li>LCP <ul> <li>We combined the discoverability and prioritization recommendations into one.</li> <li>We added a new recommendation to aim for instant navigations.</li> </ul></li> </ul> <h3 id="january_2023" data-text="January 2023" tabindex="-1">January 2023</h3> <p>This is the initial list of recommendations:</p> <ul> <li>LCP <ul> <li>Ensure the LCP resource is discoverable from the HTML source</li> <li>Ensure the LCP resource is prioritized</li> <li>Use a CDN to optimize document and resource TTFB</li> </ul></li> <li>CLS <ul> <li>Set explicit sizes on any content loaded from the page</li> <li>Ensure pages are eligible for bfcache</li> <li>Avoid animations and transitions that use layout-inducing CSS properties</li> </ul></li> <li>FID <ul> <li>Avoid or break up long tasks</li> <li>Avoid unnecessary JavaScript</li> <li>Avoid large rendering updates</li> </ul></li> </ul> <p>You can also watch this <a href="https://www.youtube.com/watch?v=mdB-J6BRReo">2023 Google I/O presentation</a> for a video summary.</p> </div> <devsite-thumb-rating position="footer"> </devsite-thumb-rating> <div class="devsite-floating-action-buttons"> </div> </article> <devsite-content-footer class="nocontent"> <p>Except as otherwise noted, the content of this page is licensed under the <a href="https://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution 4.0 License</a>, and code samples are licensed under the <a href="https://www.apache.org/licenses/LICENSE-2.0">Apache 2.0 License</a>. For details, see the <a href="https://developers.google.com/site-policies">Google Developers Site Policies</a>. Java is a registered trademark of Oracle and/or its affiliates.</p> <p>Last updated 2024-10-31 UTC.</p> </devsite-content-footer> <devsite-notification > </devsite-notification> <div class="devsite-content-data"> <template class="devsite-content-data-template"> [[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2024-10-31 UTC."],[],[]] </template> </div> </devsite-content> </main> <devsite-footer-promos class="devsite-footer"> </devsite-footer-promos> <devsite-footer-linkboxes class="devsite-footer"> <nav class="devsite-footer-linkboxes nocontent" aria-label="Footer links"> <ul class="devsite-footer-linkboxes-list"> <li class="devsite-footer-linkbox wd-footer-promo"> <h3 class="devsite-footer-linkbox-heading no-link">web.dev</h3> <ul class="devsite-footer-linkbox-list"> <li class="devsite-footer-linkbox-item"> <h3 class="devsite-footer-linkbox-heading no-link"> web.dev </h3> <div class="devsite-footer-linkbox-description">We want to help you build beautiful, accessible, fast, and secure websites that work cross-browser, and for all of your users. This site is our home for content to help you on that journey, written by members of the Chrome team, and external experts.</div> </li> </ul> </li> <li class="devsite-footer-linkbox "> <h3 class="devsite-footer-linkbox-heading no-link">Contribute</h3> <ul class="devsite-footer-linkbox-list"> <li class="devsite-footer-linkbox-item"> <a href="https://issuetracker.google.com/issues/new?component=1400680&template=1857359" class="devsite-footer-linkbox-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Footer Link (index 1)" > File a bug </a> </li> <li class="devsite-footer-linkbox-item"> <a href="https://issuetracker.google.com/issues?q=status:open%20componentid:1400680&s=created_time:desc" class="devsite-footer-linkbox-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Footer Link (index 2)" > See open issues </a> </li> </ul> </li> <li class="devsite-footer-linkbox "> <h3 class="devsite-footer-linkbox-heading no-link">Related Content</h3> <ul class="devsite-footer-linkbox-list"> <li class="devsite-footer-linkbox-item"> <a href="https://developer.chrome.com/" class="devsite-footer-linkbox-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Footer Link (index 1)" > Chrome for Developers </a> </li> <li class="devsite-footer-linkbox-item"> <a href="https://blog.chromium.org/" class="devsite-footer-linkbox-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Footer Link (index 2)" > Chromium updates </a> </li> <li class="devsite-footer-linkbox-item"> <a href="/case-studies" class="devsite-footer-linkbox-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Footer Link (index 3)" > Case studies </a> </li> <li class="devsite-footer-linkbox-item"> <a href="/shows" class="devsite-footer-linkbox-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Footer Link (index 4)" > Podcasts & shows </a> </li> </ul> </li> <li class="devsite-footer-linkbox "> <h3 class="devsite-footer-linkbox-heading no-link">Follow</h3> <ul class="devsite-footer-linkbox-list"> <li class="devsite-footer-linkbox-item"> <a href="https://twitter.com/ChromiumDev" class="devsite-footer-linkbox-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Footer Link (index 1)" > @ChromiumDev on X </a> </li> <li class="devsite-footer-linkbox-item"> <a href="https://www.youtube.com/user/ChromeDevelopers" class="devsite-footer-linkbox-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Footer Link (index 2)" > YouTube </a> </li> <li class="devsite-footer-linkbox-item"> <a href="https://www.linkedin.com/showcase/chrome-for-developers" class="devsite-footer-linkbox-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Footer Link (index 3)" > Chrome for Developers on LinkedIn </a> </li> <li class="devsite-footer-linkbox-item"> <a href="/static/blog/feed.xml" class="devsite-footer-linkbox-link gc-analytics-event" data-category="Site-Wide Custom Events" data-label="Footer Link (index 4)" > RSS </a> </li> </ul> </li> </ul> </nav> </devsite-footer-linkboxes> <devsite-footer-utility class="devsite-footer"> <div class="devsite-footer-utility nocontent"> <nav class="devsite-footer-utility-links" aria-label="Utility links"> <ul class="devsite-footer-utility-list"> <li class="devsite-footer-utility-item "> <a class="devsite-footer-utility-link gc-analytics-event" href="//policies.google.com/terms" data-category="Site-Wide Custom Events" data-label="Footer Terms link" > Terms </a> </li> <li class="devsite-footer-utility-item "> <a class="devsite-footer-utility-link gc-analytics-event" href="//policies.google.com/privacy" data-category="Site-Wide Custom Events" data-label="Footer Privacy link" > Privacy </a> </li> <li class="devsite-footer-utility-item glue-cookie-notification-bar-control"> <a class="devsite-footer-utility-link gc-analytics-event" href="#" data-category="Site-Wide Custom Events" data-label="Footer Manage cookies link" aria-hidden="true" > Manage cookies </a> </li> </ul> <devsite-language-selector> <ul role="presentation"> <li role="presentation"> <a role="menuitem" lang="en" >English</a> </li> <li role="presentation"> <a role="menuitem" lang="de" >Deutsch</a> </li> <li role="presentation"> <a role="menuitem" lang="es_419" >Español – América Latina</a> </li> <li role="presentation"> <a role="menuitem" lang="fr" >Français</a> </li> <li role="presentation"> <a role="menuitem" lang="id" >Indonesia</a> </li> <li role="presentation"> <a role="menuitem" lang="it" >Italiano</a> </li> <li role="presentation"> <a role="menuitem" lang="pl" >Polski</a> </li> <li role="presentation"> <a role="menuitem" lang="pt_br" >Português – Brasil</a> </li> <li role="presentation"> <a role="menuitem" lang="vi" >Tiếng Việt</a> </li> <li role="presentation"> <a role="menuitem" lang="tr" >Türkçe</a> </li> <li role="presentation"> <a role="menuitem" lang="ru" >Русский</a> </li> <li role="presentation"> <a role="menuitem" lang="he" >עברית</a> </li> <li role="presentation"> <a role="menuitem" lang="ar" >العربيّة</a> </li> <li role="presentation"> <a role="menuitem" lang="fa" >فارسی</a> </li> <li role="presentation"> <a role="menuitem" lang="hi" >हिंदी</a> </li> <li role="presentation"> <a role="menuitem" lang="bn" >বাংলা</a> </li> <li role="presentation"> <a role="menuitem" lang="th" >ภาษาไทย</a> </li> <li role="presentation"> <a role="menuitem" lang="zh_cn" >中文 – 简体</a> </li> <li role="presentation"> <a role="menuitem" lang="zh_tw" >中文 – 繁體</a> </li> <li role="presentation"> <a role="menuitem" lang="ja" >日本語</a> </li> <li role="presentation"> <a role="menuitem" lang="ko" >한국어</a> </li> </ul> </devsite-language-selector> </nav> </div> </devsite-footer-utility> <devsite-panel></devsite-panel> </section></section> <devsite-sitemask></devsite-sitemask> <devsite-snackbar></devsite-snackbar> <devsite-tooltip ></devsite-tooltip> <devsite-heading-link></devsite-heading-link> <devsite-analytics> <script type="application/json" analytics>[]</script> <script type="application/json" tag-management>{"at": "True", "ga4": [], "ga4p": [], "gtm": [{"id": "GTM-MZWCJPP", "purpose": 0}], "parameters": {"internalUser": "False", "language": {"machineTranslated": "False", "requested": "en", "served": "en"}, "pageType": "article", "projectName": "Articles", "signedIn": "False", "tenant": "web", "recommendations": {"sourcePage": "", "sourceType": 0, "sourceRank": 0, "sourceIdenticalDescriptions": 0, "sourceTitleWords": 0, "sourceDescriptionWords": 0, "experiment": ""}, "experiment": {"ids": ""}}}</script> </devsite-analytics> <devsite-badger></devsite-badger> <script nonce="IgWvqlHco70AYW30Y6xGQfVCRZWVA5"> (function(d,e,v,s,i,t,E){d['GoogleDevelopersObject']=i; t=e.createElement(v);t.async=1;t.src=s;E=e.getElementsByTagName(v)[0]; E.parentNode.insertBefore(t,E);})(window, document, 'script', 'https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625/web/js/app_loader.js', '[27,"en",null,"/js/devsite_app_module.js","https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625","https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625/web","https://web-dot-devsite-v2-prod-3p.appspot.com",1,null,["/_pwa/web/manifest.json","https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625/images/video-placeholder.svg","https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625/web/images/favicon.png","https://www.gstatic.com/devrel-devsite/prod/v870e399c64f7c43c99a3043db4b3a74327bb93d0914e84a0c3dba90bbfd67625/web/images/lockup.svg","https://fonts.googleapis.com/css?family=Google+Sans:400,500|Roboto:400,400italic,500,500italic,700,700italic|Roboto+Mono:400,500,700&display=swap"],1,null,[1,6,8,12,14,17,21,25,50,52,63,70,75,76,80,87,91,92,93,97,98,100,101,102,103,104,105,107,108,109,110,112,113,117,118,120,122,124,125,126,127,129,130,131,132,133,134,135,136,138,140,141,147,148,149,151,152,156,157,158,159,161,163,164,168,169,170,179,180,182,183,186,191,193,196],"AIzaSyCNm9YxQumEXwGJgTDjxoxXK6m1F-9720Q","AIzaSyCc76DZePGtoyUjqKrLdsMGk_ry7sljLbY","web.dev","AIzaSyB9bqgQ2t11WJsOX8qNsCQ6U-w91mmqF-I","AIzaSyAdYnStPdzjcJJtQ0mvIaeaMKj7_t6J_Fg",null,null,null,["Profiles__enable_page_saving","Profiles__enable_developer_profiles_callout","Profiles__enable_profile_collections","MiscFeatureFlags__developers_footer_image","Cloud__enable_llm_concierge_chat","Concierge__enable_pushui","MiscFeatureFlags__enable_firebase_utm","DevPro__enable_developer_subscriptions","MiscFeatureFlags__developers_footer_dark_image","Search__enable_page_map","Profiles__enable_completecodelab_endpoint","Search__enable_ai_eligibility_checks","BookNav__enable_tenant_cache_key","Profiles__require_profile_eligibility_for_signin","Search__enable_dynamic_content_confidential_banner","Profiles__enable_recognition_badges","OnSwitch__enable","Cloud__enable_cloudx_ping","MiscFeatureFlags__enable_variable_operator","MiscFeatureFlags__enable_project_variables","Analytics__enable_clearcut_logging","Cloud__enable_free_trial_server_call","Cloud__enable_cloud_shell_fte_user_flow","Profiles__enable_release_notes_notifications","Profiles__enable_awarding_url","CloudShell__cloud_code_overflow_menu","MiscFeatureFlags__enable_view_transitions","CloudShell__cloud_shell_button","Cloud__enable_cloud_dlp_service","TpcFeatures__enable_mirror_tenant_redirects","MiscFeatureFlags__enable_explain_this_code","Profiles__enable_public_developer_profiles","MiscFeatureFlags__emergency_css","DevPro__enable_cloud_innovators_plus","Profiles__enable_dashboard_curated_recommendations","Experiments__reqs_query_experiments","Cloud__enable_cloud_shell","Search__enable_suggestions_from_borg","Cloud__enable_cloud_facet_chat","Cloud__enable_legacy_calculator_redirect","Profiles__enable_complete_playlist_endpoint","TpcFeatures__enable_required_headers","EngEduTelemetry__enable_engedu_telemetry","Cloud__enable_cloudx_experiment_ids"],null,null,"AIzaSyA58TaKli1DculwmAmbpzLVGuWc8eCQgQc","https://developerscontentserving-pa.googleapis.com","AIzaSyDWBU60w0P9hEkr29kkksYs8Z7gvZ8u_wc","https://developerscontentsearch-pa.googleapis.com",2,4,null,"https://developerprofiles-pa.googleapis.com",[27,"web","web.dev","web.dev",null,"web-dot-devsite-v2-prod-3p.appspot.com",null,null,[null,null,null,null,null,null,null,null,null,null,null,[1],null,null,null,null,null,null,[1],null,null,null,null,[1,null,1],[1,1,null,1,1]],null,[38,null,null,null,null,null,"/images/lockup.svg","/images/touchicon-180.png",null,null,null,1,1,null,null,null,null,null,null,null,null,2,null,null,null,"/images/lockup-dark-theme.svg",[]],[],null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,[[],[1,1]],[[null,null,null,null,null,["GTM-MZWCJPP"],null,null,null,null,null,[["GTM-MZWCJPP",1]],1]],null,4]]') </script> <devsite-a11y-announce></devsite-a11y-announce> </body> </html>

CINXE.COM

The most effective ways to improve Core Web Vitals | Articles | web.dev