Spain · Madrid Completed: Apr 21, 2026 19:26 UTCMobile 375 × 812
Desktop 1440 × 900
Score: 73 / 100
Based on 8 categories, 0 sections
Fast site — your users get a smooth experience.
Several missing protections leave your users and data exposed.
Several issues make your site difficult for assistive technology users.
Well-optimized for search — your content is discoverable.
Solid infrastructure — fast server responses across the board.
Mostly compliant — a few items need attention.
Missing metadata means poor previews on social media and search.
Reasonable footprint with room for optimization.
The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.
Weights reflect general web best practices. Individual needs may differ.
Content-Security-Policy header is missing
Security gaps expose your site and users to attacks, eroding trust.
No Content-Security-Policy header found
Security gaps expose your site and users to attacks, eroding trust.
No H1 heading found
Accessibility issues exclude users with disabilities — up to 15% of your potential audience.
Soft 404: server returns HTTP 200 for non-existent pages
Accessibility issues exclude users with disabilities — up to 15% of your potential audience.
/phpinfo.php is publicly accessible
Security gaps expose your site and users to attacks, eroding trust.
High impact, low effort — start here.
High impact, requires investment.
Small gains, minimal effort.
Nothing in this quadrant — good news.
Low impact, high effort — do last.
Nothing in this quadrant — good news.
[](https://beavercheck.com/results/b10ab7f0-ee0a-4608-9a11-4e321954c9ca)<a href="https://beavercheck.com/results/b10ab7f0-ee0a-4608-9a11-4e321954c9ca"><img src="https://beavercheck.com/badge?url=https%3A%2F%2Fcaniuse.com" alt="BeaverCheck Score"></a>https://beavercheck.com/badge?url=https%3A%2F%2Fcaniuse.comThis badge auto-updates with your latest scan result.
Your site performs reasonably well, but a few targeted fixes could meaningfully improve results. The 3 security gaps leave your users exposed — modern browsers increasingly warn visitors about insecure sites. Addressing the critical issues below would have the most immediate impact on your user trust.
6 barrier(s) likely increasing bounce by ~13%.
High main-thread blocking time
+2% bouncePage is non-interactive for 290ms after first paint
Fix: Defer third-party scripts and split large bundles
No HSTS header
+1% bounceReturning visitors are briefly exposed to downgrade attacks on first request
Fix: Set Strict-Transport-Security: max-age=31536000; includeSubDomains
No Content-Security-Policy header
+1% bounceHigher XSS blast radius — one compromised script can exfiltrate the checkout form
Fix: Ship a reporting-only CSP first, then enforce once violations are clean
No Open Graph tags
+2% bounceLinks shared on LinkedIn / Slack / Facebook show bare URLs — referral clicks drop
Fix: Add og:title, og:description, og:image, og:url to the page head
No structured data
+2% bounceNo rich-result eligibility in Google — lower SERP CTR vs competitors with stars and prices
Fix: Add JSON-LD for your page type (Product, Article, FAQPage, LocalBusiness, …)
No skip-to-content link
+1% bounceKeyboard and screen-reader users must tab through the entire header on every page
Fix: Add a visible-on-focus <a href="#main">Skip to content</a> as the first focusable element
Preliminary CRO audit — each barrier links to the tab with detailed analysis.
$450 investment → $0.16/month returns + USD 157,500 risk avoided
$450
4h · 5 findings
$0.16 /mo
~$1.98 / year
USD 157,500
if kept compliant
$150 — in quick wins — start here for the fastest payback
Figures combine localized regulatory fine ceilings, search/conversion value priced against local CPC, and bandwidth waste estimates. Results depend on implementation quality and audience composition. Not legal or financial advice.
4.5 developer hours at $100/hr
Based on United States rates ($100/hr)
Start here for the best return on investment
$13,125 / month at risk
~$157,502 / year if left unfixed
$157,500
+4 more
$0.16 /mo
2058.7 MB/mo × 0.080 USD/GB
Compliance figures represent the statutory maximum fine for the most severe triggered category, capped per regulation — not the sum of per-finding penalties. Based on published regulatory fine ranges. This is not legal advice.
Unique monthly visitors from your analytics
Purchases, signups, or key actions
Optional — for revenue estimation
more engaged visitors from reduced bounce
Fix 4 critical issues to capture this value
Based on Google/Deloitte research ("Milliseconds Make Millions") showing a ~7% bounce rate increase per additional second of LCP above the 2.5s "Good" threshold.
Your site's LCP: → estimated after fixes.
These are estimates based on industry research — actual results vary
Your data stays in your browser — nothing is sent to our servers
Thanks for your feedback!
We'll use a cached audit if available, or offer to scan.
Industry-standard audits powered by Google Lighthouse.
Key metrics that affect user experience.
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
2.19 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.19 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
290 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.002
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
3.68 s
Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.
6.07 s
Audit breakdown by category with detailed findings.
Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.
Performance issues directly impact user engagement and conversion rates.
Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling
Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.
Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.
Source: Google web.dev / Lighthouse
3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.
Performance issues directly impact user engagement and conversion rates.
Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.
Performance issues directly impact user engagement and conversion rates.
Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.
Performance issues directly impact user engagement and conversion rates.
Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Duration |
|---|---|---|
| caniuse.com/css/theme-light.css?1776478325 | 704 B | |
| caniuse.com/css/home.css?1776478324 | 1.5 KiB | 304 ms |
| caniuse.com/css/main.css?1776478324 | 7.8 KiB | |
| fonts.googleapis.com/css?family=Inconsolata&display=swap | 988 B | 819 ms |
A long cache lifetime can speed up repeat visits to your page. Learn more about caching.
Performance issues directly impact user engagement and conversion rates.
| Request | Cache TTL | Transfer Size |
|---|---|---|
| /pagead/managed/js/adsense/m202604160101/show_ads_impl_fy... | 1209600.0 s | 177.5 KiB |
| caniuse.com/fonts/open-sans-300.woff2 | 0.0 ms | 14.8 KiB |
| caniuse.com/fonts/open-sans-regular.woff2 | 0.0 ms | 14.2 KiB |
These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.
Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.
Performance issues directly impact user engagement and conversion rates.
The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.
Performance issues directly impact user engagement and conversion rates.
Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| caniuse.com/css/main.css?1776478324 | 7.8 KiB | 2.2 KiB |
Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.
Multi-megabyte JavaScript bundles delay every interactive feature on the page.
This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.
Source: Google web.dev / Lighthouse
| URL | Transfer Size | Est Savings |
|---|---|---|
| /pagead/managed/js/adsense/m202604160101/show_ads_impl_fy... | 177.5 KiB | 126.3 KiB |
| www.googletagmanager.com/gtag/js?id=G-8SCDSGDGKM | 151.0 KiB | 62.1 KiB |
| caniuse.com/js/bundle.js?1776478326 | 90.7 KiB | 49.4 KiB |
| pagead2.googlesyndication.com/pagead/js/adsbygoogle.js | 54.2 KiB | 24.4 KiB |
More information about the performance of your application. These numbers don't directly affect the Performance score.
These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.
These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.
If your robots.txt file is malformed, crawlers may not be able to understand how you want your website to be crawled or indexed. Learn more about robots.txt.
Performance issues directly impact user engagement and conversion rates.
| Line # | Content | Error |
|---|---|---|
| 1 | <!doctype html> | Syntax not understood |
| 2 | <html dir="ltr" lang="en-US" class="no-js"> | Syntax not understood |
| 3 | <head> | Syntax not understood |
| 4 | <meta charset="utf-8" /> | Syntax not understood |
| 5 | <title>"robots.txt" | Can I use... Support tables for HTML5, CSS3, etc</title> | Syntax not understood |
| 7 | <meta name="viewport" content="width=device-width"> | Syntax not understood |
| 9 | <link rel="alternate" type="application/atom+xml" title="Can I Use updates" href="/feed"> | Syntax not understood |
| 10 | <link href="//fonts.googleapis.com/css?family=Inconsolata&display=swap" rel="stylesheet"> | Syntax not understood |
| 11 | <link rel="icon" href="/img/favicon-128.png" sizes="16x16 32x32 64x64 128x128" type="image/png"/> | Syntax not understood |
| 12 | <link rel="apple-touch-icon" href="/img/favicon-128.png"> | Syntax not understood |
| 14 | <link rel="stylesheet" href="/css/main.css?1776478324" media="all"> | Syntax not understood |
| 15 | <link rel="stylesheet" data-theme="light" href="/css/theme-light.css?1776478325" media="all"> | Syntax not understood |
| 16 | <link rel="stylesheet" data-theme="dark" href="/css/theme-dark.css?1776478325" media="(prefers-color-scheme: dark)"> | Unknown directive |
| 17 | <meta name="Description" content=""Can I use" provides up-to-date browser support tables for support of front-end web technologies on desktop and mobile web browsers."> | Syntax not understood |
| 18 | <meta name="keywords" content="web browser compatibility support html css svg html5 css3 opera chrome firefox safari internet explorer"> | Syntax not understood |
| 19 | <link rel="search" href="/opensearch.xml" type="application/opensearchdescription+xml" title="Can I use"/> | Syntax not understood |
| 20 | <link rel="preconnect" href="https://ipinfo.io"> | Unknown directive |
| 21 | <link rel="preconnect" href="https://www.google-analytics.com"> | Unknown directive |
| 22 | <base href="/" /> | Syntax not understood |
| 23 | <script> | Syntax not understood |
| 24 | document.write('<style>.static-only {display:none}</style>'); | Unknown directive |
| 25 | </script> | Syntax not understood |
| 27 | <script async src="https://www.googletagmanager.com/gtag/js?id=G-8SCDSGDGKM"></script> | Unknown directive |
| 28 | <script> | Syntax not understood |
| 29 | window.dataLayer = window.dataLayer || []; | Syntax not understood |
| 30 | function gtag(){dataLayer.push(arguments);} | Syntax not understood |
| 31 | gtag('js', new Date()); | Syntax not understood |
| 33 | gtag('config', 'G-8SCDSGDGKM'); | Syntax not understood |
| 34 | </script> | Syntax not understood |
| 36 | <script> | Syntax not understood |
| 37 | (function() { | Syntax not understood |
| 38 | if (!window.customElements) { | Syntax not understood |
| 39 | var s = document.createElement('script'); | Syntax not understood |
| 40 | s.src = '/legacy-handler.js'; | Syntax not understood |
| 41 | document.getElementsByTagName('head')[0].appendChild(s); | Syntax not understood |
| 42 | } | Syntax not understood |
| 43 | }()); | Syntax not understood |
| 44 | </script> | Syntax not understood |
| 45 | <!--[if IE]><script src="/legacy-handler.js"></script><![endif]--><script defer src="js-data/data.js?1776729872"></script><script defer src="js/bundle.js?1776478326"></script></head> | Syntax not understood |
| 46 | <body class="is-home"> | Syntax not understood |
| 47 | <div id="main" class="ciu-main-wrap"> | Syntax not understood |
| 49 | <header class="ciu-page-header"> | Syntax not understood |
| 50 | <nav role="navigation" id="tab-container"> | Syntax not understood |
| 51 | <ul class="ciu-page-header__primary-nav"> | Syntax not understood |
| 52 | <li class="site-nav-item js-site-nav"><a href="/" data-route="home">Home</a></li> | Syntax not understood |
| 53 | <li class="site-nav-item js-site-nav site-nav-item--news"><a href="/ciu/news" data-route="news">News</a></li> | Syntax not understood |
| 54 | </ul> | Syntax not understood |
| 56 | <ul class="ciu-page-header__secondary-nav"> | Syntax not understood |
| 57 | <li class="site-nav-item js-site-nav site-nav-item--comparison"><a href="/ciu/comparison" data-route="comparison">Compare<span class="site-nav__extra-text"> browsers</span></a></li> | Syntax not understood |
| 58 | <li class="site-nav-item js-site-nav site-nav-item--last "><a href="/ciu/about" data-route="about">About</a></li> | Syntax not understood |
| 59 | </ul> | Syntax not understood |
| 61 | <a class="news js-news" data-newstime="1772668800" href="https://caniuse.com/loading-lazy-media"><span class="date">March 5, 2026 -</span> New feature: Lazy loading via attribute for video & audio</a> </nav> | Unknown directive |
| 64 | <section class="ciu-search"> | Syntax not understood |
| 65 | <div class="ciu-search__inner js-search"> | Syntax not understood |
| 66 | <a href="/" class="ciu-search__label">Can I use</a> | Syntax not understood |
| 67 | <form action="/" class="ciu-search__form"> | Syntax not understood |
| 68 | <label class="ciu-search__a11y-label" for="feat_search">Search</label> | Syntax not understood |
| 69 | <input type="text" class="ciu-search__input" id="feat_search" name="search" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false" autofocus value="robots.txt"> | Syntax not understood |
| 70 | <input type="hidden" name="static" value="1"> | Syntax not understood |
| 71 | </form> | Syntax not understood |
| 72 | ? | Syntax not understood |
| 73 | <button class="options-toggle js-options-toggle"> | Syntax not understood |
| 74 | <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 16 16" class="icon"> | Unknown directive |
| 75 | <path d="M16,8.87V7L15.74,7l-1.95-.64-.52-1.25,1-2.12L13,1.67l-.25.12-1.82.93L9.66,2.2,8.87,0H7.05L7,.26,6.33,2.21l-1.25.52L3,1.73,1.67,3l.12.25.93,1.82L2.2,6.34,0,7.13V8.95L.26,9l2,.64.52,1.25L1.73,13,3,14.33l.25-.12,1.82-.93,1.26.52L7.13,16H8.95L9,15.74l.64-2,1.26-.52,2.11,1L14.33,13l-.12-.25-.93-1.82.52-1.26ZM8,10.55A2.55,2.55,0,1,1,10.55,8,2.55,2.55,0,0,1,8,10.55Z"/> | Syntax not understood |
| 76 | </svg> | Syntax not understood |
| 77 | <span> | Syntax not understood |
| 78 | Settings | Syntax not understood |
| 79 | </span> | Syntax not understood |
| 80 | </button> | Syntax not understood |
| 81 | </div> | Syntax not understood |
| 83 | <div class="search-result-info js-search-result-info">0 results found. <p>Why not <a href="https://github.com/Fyrd/caniuse/issues?utf8=%E2%9C%93&q=is%3Aissue+is%3Aopen+thnthnth">suggest this feature be added?</a></p></div> | Unknown directive |
| 84 | </section> | Syntax not understood |
| 86 | </header> | Syntax not understood |
| 88 | <main class="ciu-page-content js-content" data-static-id="search"> | Syntax not understood |
| 89 | </main> | Syntax not understood |
| 91 | <aside class="bottom-ad"> | Syntax not understood |
| 92 | <script async src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script> | Syntax not understood |
| 93 | <!-- Bottom leaderboard --> | Syntax not understood |
| 94 | <ins class="adsbygoogle" | Syntax not understood |
| 95 | style="display:inline-block;width:728px;height:90px" | Unknown directive |
| 96 | data-ad-client="ca-pub-3347535679733957" | Syntax not understood |
| 97 | data-ad-slot="1205929339"></ins> | Syntax not understood |
| 98 | <script> | Syntax not understood |
| 99 | (adsbygoogle = window.adsbygoogle || []).push({}); | Syntax not understood |
| 100 | </script> | Syntax not understood |
| 101 | </aside> | Syntax not understood |
| 103 | <footer class="ciu-footer"> | Syntax not understood |
| 104 | <div class="footer__section footer__primary"> | Syntax not understood |
| 105 | <h3 class="footer__heading">Can I use...</h3> | Syntax not understood |
| 106 | <p class="site-description">Browser support tables for modern web technologies</p> | Syntax not understood |
| 107 | <p>Created & maintained by <a class="external-link" href="https://front-end.social/@fyrd">@Fyrd</a>, design by <a class="external-link" href="https://mastodon.world/@lensco">@Lensco</a>.</p> | Unknown directive |
| 108 | <p>Support data contributions by the GitHub <a class="external-link" href="https://github.com/Fyrd/caniuse/graphs/contributors">community</a>. | Unknown directive |
| 110 | <p id="usage_note"> | Syntax not understood |
| 111 | Usage share statistics by <a class="external-link" href="http://gs.statcounter.com/">StatCounter GlobalStats</a> for March, 2026 </p> | Unknown directive |
| 113 | <p>Location detection provided by <a class="external-link" href="//ipinfo.io">ipinfo.io</a>. | Syntax not understood |
| 114 | </p> | Syntax not understood |
| 116 | <p> | Syntax not understood |
| 117 | Browser testing done via | Syntax not understood |
| 118 | <a class="external-link" href="https://www.browserstack.com?ref=caniuse-source&caniuse_source=brand-asset&utm_source=caniuse&utm_medium=partnered&utm_campaigncode=701OW000008y9C1YAI" target="_blank"> | Unknown directive |
| 119 | <img src="/img/browserstack.svg" alt="BrowserStack" width="140" height="28" loading="lazy"> | Syntax not understood |
| 120 | </a> | Syntax not understood |
| 121 | </p> | Syntax not understood |
| 123 | </div> | Syntax not understood |
| 125 | <div class="footer__section footer__patreon"> | Syntax not understood |
| 126 | <h3 class="footer__heading">Support via Patreon</h3> | Syntax not understood |
| 128 | <p>Become a caniuse Patron to support the site and disable ads for only $1/month!</p> | Syntax not understood |
| 130 | <div class="patreon-button"> | Syntax not understood |
| 131 | <a href="https://www.patreon.com/join/caniuse"> | Unknown directive |
| 132 | <img src="/img/become_a_patron_button.png" width="163" height="38" alt="Become a Patron!" loading="lazy"> | Syntax not understood |
| 133 | </a> | Syntax not understood |
| 134 | </div> | Syntax not understood |
| 135 | <p> | Syntax not understood |
| 136 | or <a class="external-link" href="http://www.patreon.com/oauth2/authorize?response_type=code&client_id=efdd32564c7459c2c0dcd644b984e6948070b23b72961a3b9fb32ab3ad797184&redirect_uri=https%3A%2F%2Fcaniuse.com">Log in</a> | Unknown directive |
| 137 | </p> | Syntax not understood |
| 138 | </div> | Syntax not understood |
| 140 | <div class="footer__section footer__links"> | Syntax not understood |
| 141 | <h3 class="footer__heading">Site links</h3> | Syntax not understood |
| 142 | <ol class="footer__list"> | Syntax not understood |
| 143 | <li class="footer__list-item"> | Syntax not understood |
| 144 | <a href="/">Home</a> | Syntax not understood |
| 145 | </li> | Syntax not understood |
| 146 | <li class="footer__list-item"> | Syntax not understood |
| 147 | <a href="/ciu/index">Feature index</a> | Syntax not understood |
| 148 | </li> | Syntax not understood |
| 149 | <li class="footer__list-item"> | Syntax not understood |
| 150 | <a href="/usage-table">Browser usage table</a> | Syntax not understood |
| 151 | </li> | Syntax not understood |
| 152 | <li class="footer__list-item"> | Syntax not understood |
| 153 | <a href="/issue-list">Feature suggestion list</a> | Syntax not understood |
| 154 | </li> | Syntax not understood |
| 155 | <li class="footer__list-item"> | Syntax not understood |
| 156 | <a href="https://github.com/fyrd/caniuse">Caniuse data on GitHub</a> | Unknown directive |
| 157 | </li> | Syntax not understood |
| 158 | </ol> | Syntax not understood |
| 159 | </div> | Syntax not understood |
| 161 | <div class="footer__section footer__legend"> | Syntax not understood |
| 162 | <section class="ciu-legend js-legend"> | Syntax not understood |
| 163 | <h2 class="ciu-legend__header">Legend</h2> | Syntax not understood |
| 164 | <ul class="ciu-legend__list"> | Syntax not understood |
| 165 | <li class="ciu-legend__item"> | Syntax not understood |
| 166 | <span class="y ciu-legend__color">Green</span> | Syntax not understood |
| 167 | <span class="ciu-legend__symbol">✅</span> | Syntax not understood |
| 168 | = Supported | Syntax not understood |
| 169 | </li> | Syntax not understood |
| 170 | <li class="ciu-legend__item"> | Syntax not understood |
| 171 | <span class="n ciu-legend__color">Red</span> | Syntax not understood |
| 172 | <span class="ciu-legend__symbol">❌</span> | Syntax not understood |
| 173 | = Not supported | Syntax not understood |
| 174 | </li> | Syntax not understood |
| 175 | <li class="ciu-legend__item"> | Syntax not understood |
| 176 | <span class="a ciu-legend__color">Greenish yellow</span> | Syntax not understood |
| 177 | <span class="ciu-legend__symbol">◐</span> | Syntax not understood |
| 178 | = Partial support | Syntax not understood |
| 179 | </li> | Syntax not understood |
| 180 | <li class="ciu-legend__item"> | Syntax not understood |
| 181 | <span class="u ciu-legend__color">Gray</span> | Syntax not understood |
| 182 | <span class="ciu-legend__symbol">﹖</span> | Syntax not understood |
| 183 | = Support unknown | Syntax not understood |
| 184 | </li> | Syntax not understood |
| 185 | </ul> | Syntax not understood |
| 186 | </section> | Syntax not understood |
| 187 | </div> | Syntax not understood |
| 188 | </footer> | Syntax not understood |
| 189 | </div><!-- /all --> | Syntax not understood |
| 190 | </body> | Syntax not understood |
| 191 | </html> | Syntax not understood |
To appear in search results, crawlers need access to your app.
Industry-standard audits powered by Google Lighthouse. — Desktop
Key metrics that affect user experience. — Desktop
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
1.09 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.09 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
0 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.019
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.62 s
Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.
1.09 s
Audit breakdown by category with detailed findings.
Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.
Performance issues directly impact user engagement and conversion rates.
Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling
Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.
Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.
Source: Google web.dev / Lighthouse
3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.
Performance issues directly impact user engagement and conversion rates.
Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.
Performance issues directly impact user engagement and conversion rates.
| URL | Est Savings |
|---|---|
| /s/opensans/v44/memvYaGs126MiZpBA-UvWbX2vVnXBbObj2OVTS-mu... | 40 ms |
Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.
Performance issues directly impact user engagement and conversion rates.
Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Duration |
|---|---|---|
| caniuse.com/css/theme-light.css?1776478325 | 704 B | |
| caniuse.com/css/home.css?1776478324 | 1.5 KiB | 193 ms |
| caniuse.com/css/main.css?1776478324 | 7.8 KiB | |
| fonts.googleapis.com/css?family=Inconsolata&display=swap | 991 B | 269 ms |
A long cache lifetime can speed up repeat visits to your page. Learn more about caching.
Performance issues directly impact user engagement and conversion rates.
| Request | Cache TTL | Transfer Size |
|---|---|---|
| /pagead/managed/js/activeview/current/ufs_web_display.js | 3600.0 s | 73.1 KiB |
| /pagead/managed/js/adsense/m202604160101/show_ads_impl_fy... | 1209600.0 s | 177.5 KiB |
| caniuse.com/fonts/open-sans-300.woff2 | 0.0 ms | 14.8 KiB |
| caniuse.com/fonts/open-sans-regular.woff2 | 0.0 ms | 14.2 KiB |
| /mysidia/9475976b3d2af33fba37207c76515039.js?tag=addon/my... | 86400.0 s | 17.2 KiB |
| /pagead/js/r20260420/r20110914/client/qs_click_protection... | 1209600.0 s | 8.5 KiB |
| pagead2.googlesyndication.com/pagead/js/r20260420/r20110914/abg_lite_fy2021.js | 1209600.0 s | 8.4 KiB |
| /pagead/js/r20260420/r20110914/client/window_focus_fy2021.js | 1209600.0 s | 1.2 KiB |
| /pagead/js/r20260420/r20110914/client/load_preloaded_reso... | 1209600.0 s | 840 B |
These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.
Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| caniuse.com/css/main.css?1776478324 | 7.8 KiB | 2.2 KiB |
Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.
Multi-megabyte JavaScript bundles delay every interactive feature on the page.
This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.
Source: Google web.dev / Lighthouse
| URL | Transfer Size | Est Savings |
|---|---|---|
| /pagead/managed/js/adsense/m202604160101/show_ads_impl_fy... | 177.5 KiB | 133.1 KiB |
| www.googletagmanager.com/gtag/js?id=G-8SCDSGDGKM | 151.0 KiB | 59.9 KiB |
| caniuse.com/js/bundle.js?1776478326 | 90.7 KiB | 49.4 KiB |
| pagead2.googlesyndication.com/pagead/js/adsbygoogle.js | 54.2 KiB | 26.7 KiB |
More information about the performance of your application. These numbers don't directly affect the Performance score.
These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.
These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.
If your robots.txt file is malformed, crawlers may not be able to understand how you want your website to be crawled or indexed. Learn more about robots.txt.
Performance issues directly impact user engagement and conversion rates.
| Line # | Content | Error |
|---|---|---|
| 1 | <!doctype html> | Syntax not understood |
| 2 | <html dir="ltr" lang="en-US" class="no-js"> | Syntax not understood |
| 3 | <head> | Syntax not understood |
| 4 | <meta charset="utf-8" /> | Syntax not understood |
| 5 | <title>"robots.txt" | Can I use... Support tables for HTML5, CSS3, etc</title> | Syntax not understood |
| 7 | <meta name="viewport" content="width=device-width"> | Syntax not understood |
| 9 | <link rel="alternate" type="application/atom+xml" title="Can I Use updates" href="/feed"> | Syntax not understood |
| 10 | <link href="//fonts.googleapis.com/css?family=Inconsolata&display=swap" rel="stylesheet"> | Syntax not understood |
| 11 | <link rel="icon" href="/img/favicon-128.png" sizes="16x16 32x32 64x64 128x128" type="image/png"/> | Syntax not understood |
| 12 | <link rel="apple-touch-icon" href="/img/favicon-128.png"> | Syntax not understood |
| 14 | <link rel="stylesheet" href="/css/main.css?1776478324" media="all"> | Syntax not understood |
| 15 | <link rel="stylesheet" data-theme="light" href="/css/theme-light.css?1776478325" media="all"> | Syntax not understood |
| 16 | <link rel="stylesheet" data-theme="dark" href="/css/theme-dark.css?1776478325" media="(prefers-color-scheme: dark)"> | Unknown directive |
| 17 | <meta name="Description" content=""Can I use" provides up-to-date browser support tables for support of front-end web technologies on desktop and mobile web browsers."> | Syntax not understood |
| 18 | <meta name="keywords" content="web browser compatibility support html css svg html5 css3 opera chrome firefox safari internet explorer"> | Syntax not understood |
| 19 | <link rel="search" href="/opensearch.xml" type="application/opensearchdescription+xml" title="Can I use"/> | Syntax not understood |
| 20 | <link rel="preconnect" href="https://ipinfo.io"> | Unknown directive |
| 21 | <link rel="preconnect" href="https://www.google-analytics.com"> | Unknown directive |
| 22 | <base href="/" /> | Syntax not understood |
| 23 | <script> | Syntax not understood |
| 24 | document.write('<style>.static-only {display:none}</style>'); | Unknown directive |
| 25 | </script> | Syntax not understood |
| 27 | <script async src="https://www.googletagmanager.com/gtag/js?id=G-8SCDSGDGKM"></script> | Unknown directive |
| 28 | <script> | Syntax not understood |
| 29 | window.dataLayer = window.dataLayer || []; | Syntax not understood |
| 30 | function gtag(){dataLayer.push(arguments);} | Syntax not understood |
| 31 | gtag('js', new Date()); | Syntax not understood |
| 33 | gtag('config', 'G-8SCDSGDGKM'); | Syntax not understood |
| 34 | </script> | Syntax not understood |
| 36 | <script> | Syntax not understood |
| 37 | (function() { | Syntax not understood |
| 38 | if (!window.customElements) { | Syntax not understood |
| 39 | var s = document.createElement('script'); | Syntax not understood |
| 40 | s.src = '/legacy-handler.js'; | Syntax not understood |
| 41 | document.getElementsByTagName('head')[0].appendChild(s); | Syntax not understood |
| 42 | } | Syntax not understood |
| 43 | }()); | Syntax not understood |
| 44 | </script> | Syntax not understood |
| 45 | <!--[if IE]><script src="/legacy-handler.js"></script><![endif]--><script defer src="js-data/data.js?1776729872"></script><script defer src="js/bundle.js?1776478326"></script></head> | Syntax not understood |
| 46 | <body class="is-home"> | Syntax not understood |
| 47 | <div id="main" class="ciu-main-wrap"> | Syntax not understood |
| 49 | <header class="ciu-page-header"> | Syntax not understood |
| 50 | <nav role="navigation" id="tab-container"> | Syntax not understood |
| 51 | <ul class="ciu-page-header__primary-nav"> | Syntax not understood |
| 52 | <li class="site-nav-item js-site-nav"><a href="/" data-route="home">Home</a></li> | Syntax not understood |
| 53 | <li class="site-nav-item js-site-nav site-nav-item--news"><a href="/ciu/news" data-route="news">News</a></li> | Syntax not understood |
| 54 | </ul> | Syntax not understood |
| 56 | <ul class="ciu-page-header__secondary-nav"> | Syntax not understood |
| 57 | <li class="site-nav-item js-site-nav site-nav-item--comparison"><a href="/ciu/comparison" data-route="comparison">Compare<span class="site-nav__extra-text"> browsers</span></a></li> | Syntax not understood |
| 58 | <li class="site-nav-item js-site-nav site-nav-item--last "><a href="/ciu/about" data-route="about">About</a></li> | Syntax not understood |
| 59 | </ul> | Syntax not understood |
| 61 | <a class="news js-news" data-newstime="1772668800" href="https://caniuse.com/loading-lazy-media"><span class="date">March 5, 2026 -</span> New feature: Lazy loading via attribute for video & audio</a> </nav> | Unknown directive |
| 64 | <section class="ciu-search"> | Syntax not understood |
| 65 | <div class="ciu-search__inner js-search"> | Syntax not understood |
| 66 | <a href="/" class="ciu-search__label">Can I use</a> | Syntax not understood |
| 67 | <form action="/" class="ciu-search__form"> | Syntax not understood |
| 68 | <label class="ciu-search__a11y-label" for="feat_search">Search</label> | Syntax not understood |
| 69 | <input type="text" class="ciu-search__input" id="feat_search" name="search" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false" autofocus value="robots.txt"> | Syntax not understood |
| 70 | <input type="hidden" name="static" value="1"> | Syntax not understood |
| 71 | </form> | Syntax not understood |
| 72 | ? | Syntax not understood |
| 73 | <button class="options-toggle js-options-toggle"> | Syntax not understood |
| 74 | <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 16 16" class="icon"> | Unknown directive |
| 75 | <path d="M16,8.87V7L15.74,7l-1.95-.64-.52-1.25,1-2.12L13,1.67l-.25.12-1.82.93L9.66,2.2,8.87,0H7.05L7,.26,6.33,2.21l-1.25.52L3,1.73,1.67,3l.12.25.93,1.82L2.2,6.34,0,7.13V8.95L.26,9l2,.64.52,1.25L1.73,13,3,14.33l.25-.12,1.82-.93,1.26.52L7.13,16H8.95L9,15.74l.64-2,1.26-.52,2.11,1L14.33,13l-.12-.25-.93-1.82.52-1.26ZM8,10.55A2.55,2.55,0,1,1,10.55,8,2.55,2.55,0,0,1,8,10.55Z"/> | Syntax not understood |
| 76 | </svg> | Syntax not understood |
| 77 | <span> | Syntax not understood |
| 78 | Settings | Syntax not understood |
| 79 | </span> | Syntax not understood |
| 80 | </button> | Syntax not understood |
| 81 | </div> | Syntax not understood |
| 83 | <div class="search-result-info js-search-result-info">0 results found. <p>Why not <a href="https://github.com/Fyrd/caniuse/issues?utf8=%E2%9C%93&q=is%3Aissue+is%3Aopen+thnthnth">suggest this feature be added?</a></p></div> | Unknown directive |
| 84 | </section> | Syntax not understood |
| 86 | </header> | Syntax not understood |
| 88 | <main class="ciu-page-content js-content" data-static-id="search"> | Syntax not understood |
| 89 | </main> | Syntax not understood |
| 91 | <aside class="bottom-ad"> | Syntax not understood |
| 92 | <script async src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script> | Syntax not understood |
| 93 | <!-- Bottom leaderboard --> | Syntax not understood |
| 94 | <ins class="adsbygoogle" | Syntax not understood |
| 95 | style="display:inline-block;width:728px;height:90px" | Unknown directive |
| 96 | data-ad-client="ca-pub-3347535679733957" | Syntax not understood |
| 97 | data-ad-slot="1205929339"></ins> | Syntax not understood |
| 98 | <script> | Syntax not understood |
| 99 | (adsbygoogle = window.adsbygoogle || []).push({}); | Syntax not understood |
| 100 | </script> | Syntax not understood |
| 101 | </aside> | Syntax not understood |
| 103 | <footer class="ciu-footer"> | Syntax not understood |
| 104 | <div class="footer__section footer__primary"> | Syntax not understood |
| 105 | <h3 class="footer__heading">Can I use...</h3> | Syntax not understood |
| 106 | <p class="site-description">Browser support tables for modern web technologies</p> | Syntax not understood |
| 107 | <p>Created & maintained by <a class="external-link" href="https://front-end.social/@fyrd">@Fyrd</a>, design by <a class="external-link" href="https://mastodon.world/@lensco">@Lensco</a>.</p> | Unknown directive |
| 108 | <p>Support data contributions by the GitHub <a class="external-link" href="https://github.com/Fyrd/caniuse/graphs/contributors">community</a>. | Unknown directive |
| 110 | <p id="usage_note"> | Syntax not understood |
| 111 | Usage share statistics by <a class="external-link" href="http://gs.statcounter.com/">StatCounter GlobalStats</a> for March, 2026 </p> | Unknown directive |
| 113 | <p>Location detection provided by <a class="external-link" href="//ipinfo.io">ipinfo.io</a>. | Syntax not understood |
| 114 | </p> | Syntax not understood |
| 116 | <p> | Syntax not understood |
| 117 | Browser testing done via | Syntax not understood |
| 118 | <a class="external-link" href="https://www.browserstack.com?ref=caniuse-source&caniuse_source=brand-asset&utm_source=caniuse&utm_medium=partnered&utm_campaigncode=701OW000008y9C1YAI" target="_blank"> | Unknown directive |
| 119 | <img src="/img/browserstack.svg" alt="BrowserStack" width="140" height="28" loading="lazy"> | Syntax not understood |
| 120 | </a> | Syntax not understood |
| 121 | </p> | Syntax not understood |
| 123 | </div> | Syntax not understood |
| 125 | <div class="footer__section footer__patreon"> | Syntax not understood |
| 126 | <h3 class="footer__heading">Support via Patreon</h3> | Syntax not understood |
| 128 | <p>Become a caniuse Patron to support the site and disable ads for only $1/month!</p> | Syntax not understood |
| 130 | <div class="patreon-button"> | Syntax not understood |
| 131 | <a href="https://www.patreon.com/join/caniuse"> | Unknown directive |
| 132 | <img src="/img/become_a_patron_button.png" width="163" height="38" alt="Become a Patron!" loading="lazy"> | Syntax not understood |
| 133 | </a> | Syntax not understood |
| 134 | </div> | Syntax not understood |
| 135 | <p> | Syntax not understood |
| 136 | or <a class="external-link" href="http://www.patreon.com/oauth2/authorize?response_type=code&client_id=efdd32564c7459c2c0dcd644b984e6948070b23b72961a3b9fb32ab3ad797184&redirect_uri=https%3A%2F%2Fcaniuse.com">Log in</a> | Unknown directive |
| 137 | </p> | Syntax not understood |
| 138 | </div> | Syntax not understood |
| 140 | <div class="footer__section footer__links"> | Syntax not understood |
| 141 | <h3 class="footer__heading">Site links</h3> | Syntax not understood |
| 142 | <ol class="footer__list"> | Syntax not understood |
| 143 | <li class="footer__list-item"> | Syntax not understood |
| 144 | <a href="/">Home</a> | Syntax not understood |
| 145 | </li> | Syntax not understood |
| 146 | <li class="footer__list-item"> | Syntax not understood |
| 147 | <a href="/ciu/index">Feature index</a> | Syntax not understood |
| 148 | </li> | Syntax not understood |
| 149 | <li class="footer__list-item"> | Syntax not understood |
| 150 | <a href="/usage-table">Browser usage table</a> | Syntax not understood |
| 151 | </li> | Syntax not understood |
| 152 | <li class="footer__list-item"> | Syntax not understood |
| 153 | <a href="/issue-list">Feature suggestion list</a> | Syntax not understood |
| 154 | </li> | Syntax not understood |
| 155 | <li class="footer__list-item"> | Syntax not understood |
| 156 | <a href="https://github.com/fyrd/caniuse">Caniuse data on GitHub</a> | Unknown directive |
| 157 | </li> | Syntax not understood |
| 158 | </ol> | Syntax not understood |
| 159 | </div> | Syntax not understood |
| 161 | <div class="footer__section footer__legend"> | Syntax not understood |
| 162 | <section class="ciu-legend js-legend"> | Syntax not understood |
| 163 | <h2 class="ciu-legend__header">Legend</h2> | Syntax not understood |
| 164 | <ul class="ciu-legend__list"> | Syntax not understood |
| 165 | <li class="ciu-legend__item"> | Syntax not understood |
| 166 | <span class="y ciu-legend__color">Green</span> | Syntax not understood |
| 167 | <span class="ciu-legend__symbol">✅</span> | Syntax not understood |
| 168 | = Supported | Syntax not understood |
| 169 | </li> | Syntax not understood |
| 170 | <li class="ciu-legend__item"> | Syntax not understood |
| 171 | <span class="n ciu-legend__color">Red</span> | Syntax not understood |
| 172 | <span class="ciu-legend__symbol">❌</span> | Syntax not understood |
| 173 | = Not supported | Syntax not understood |
| 174 | </li> | Syntax not understood |
| 175 | <li class="ciu-legend__item"> | Syntax not understood |
| 176 | <span class="a ciu-legend__color">Greenish yellow</span> | Syntax not understood |
| 177 | <span class="ciu-legend__symbol">◐</span> | Syntax not understood |
| 178 | = Partial support | Syntax not understood |
| 179 | </li> | Syntax not understood |
| 180 | <li class="ciu-legend__item"> | Syntax not understood |
| 181 | <span class="u ciu-legend__color">Gray</span> | Syntax not understood |
| 182 | <span class="ciu-legend__symbol">﹖</span> | Syntax not understood |
| 183 | = Support unknown | Syntax not understood |
| 184 | </li> | Syntax not understood |
| 185 | </ul> | Syntax not understood |
| 186 | </section> | Syntax not understood |
| 187 | </div> | Syntax not understood |
| 188 | </footer> | Syntax not understood |
| 189 | </div><!-- /all --> | Syntax not understood |
| 190 | </body> | Syntax not understood |
| 191 | </html> | Syntax not understood |
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