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(Click to learn more.)"><span class="icon icon-question-mark "></span></a></div></form></li><li class=" "><a data-locale="de" href="/de/docs/Web/HTTP" class="button submenu-item"><span>Deutsch</span><span title="Diese Übersetzung ist Teil eines Experiments."><span class="icon icon-experimental "></span></span></a></li><li class=" "><a data-locale="es" href="/es/docs/Web/HTTP" class="button submenu-item"><span>Español</span></a></li><li class=" "><a data-locale="fr" href="/fr/docs/Web/HTTP" class="button submenu-item"><span>Français</span></a></li><li class=" "><a data-locale="ja" href="/ja/docs/Web/HTTP" class="button submenu-item"><span>日本語</span></a></li><li class=" "><a data-locale="ko" href="/ko/docs/Web/HTTP" class="button submenu-item"><span>한국어</span></a></li><li class=" "><a data-locale="pt-BR" href="/pt-BR/docs/Web/HTTP" class="button submenu-item"><span>Português (do Brasil)</span></a></li><li class=" "><a data-locale="ru" href="/ru/docs/Web/HTTP" class="button 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class="sidebar-filter-input-field false" type="text" placeholder="Filter" value=""/><button type="button" class="button action has-icon clear-sidebar-filter-button"><span class="button-wrap"><span class="icon icon-cancel "></span><span class="visually-hidden">Clear filter input</span></span></button></div></section></header><div class="sidebar-inner-nav"><div class="in-nav-toc"><div class="document-toc-container"><section class="document-toc"><header><h2 class="document-toc-heading">In this article</h2></header><ul class="document-toc-list"><li class="document-toc-item "><a class="document-toc-link" href="#references">References</a></li><li class="document-toc-item "><a class="document-toc-link" href="#http_guides">HTTP guides</a></li><li class="document-toc-item "><a class="document-toc-link" href="#tools_resources">Tools & resources</a></li></ul></section></div></div><div class="sidebar-body"> <ol> <li class="section"><em><a href="/en-US/docs/Web/HTTP" aria-current="page">HTTP</a></em></li> <li class="section no-link">Guides</li> <li><a href="/en-US/docs/Web/HTTP/Overview">An overview of HTTP</a></li> <li><a href="/en-US/docs/Web/HTTP/Session">A typical HTTP session</a></li> <li><a href="/en-US/docs/Web/HTTP/Messages">HTTP messages</a></li> <li><a href="/en-US/docs/Web/HTTP/MIME_types">MIME types (IANA media types)</a></li> <li><a href="/en-US/docs/Web/HTTP/Compression">Compression in HTTP</a></li> <li><a href="/en-US/docs/Web/HTTP/Caching">HTTP caching</a></li> <li><a href="/en-US/docs/Web/HTTP/Authentication">HTTP authentication</a></li> <li><a href="/en-US/docs/Web/HTTP/Cookies">Using HTTP cookies</a></li> <li><a href="/en-US/docs/Web/HTTP/Redirections">Redirections in HTTP</a></li> <li><a href="/en-US/docs/Web/HTTP/Conditional_requests">HTTP conditional requests</a></li> <li><a href="/en-US/docs/Web/HTTP/Range_requests">HTTP range requests</a></li> <li><a href="/en-US/docs/Web/HTTP/Content_negotiation">Content negotiation</a></li> <li><a href="/en-US/docs/Web/HTTP/Connection_management_in_HTTP_1.x">Connection management in HTTP/1.x</a></li> <li><a href="/en-US/docs/Web/HTTP/Evolution_of_HTTP">Evolution of HTTP</a></li> <li><a href="/en-US/docs/Web/HTTP/Protocol_upgrade_mechanism">Protocol upgrade mechanism</a></li> <li><a href="/en-US/docs/Web/HTTP/Proxy_servers_and_tunneling">Proxy servers and tunneling</a></li> <li><a href="/en-US/docs/Web/HTTP/Client_hints">HTTP Client hints</a></li> <li class="toggle"> <details> <summary>Security and privacy</summary> <ol> <li><a href="/en-US/docs/Web/Security/Practical_implementation_guides">Practical security implementation guides</a></li> <li><a href="/en-US/observatory">HTTP Observatory</a></li> <li><a href="/en-US/docs/Web/HTTP/Permissions_Policy">Permissions Policy</a></li> <li><a href="/en-US/docs/Web/HTTP/CSP">Content Security Policy (CSP)</a></li> <li><a href="/en-US/docs/Web/HTTP/CORS">Cross-Origin Resource Sharing (CORS)</a></li> <li><a href="/en-US/docs/Web/HTTP/Cross-Origin_Resource_Policy">Cross-Origin Resource Policy (CORP)</a></li> <li><a href="/en-US/docs/Web/HTTP/Headers/Strict-Transport-Security">Strict-Transport-Security</a></li> </ol> </details> </li> <li class="section no-link">References</li> <li class="toggle"> <details> <summary>HTTP headers</summary> <ol><li><a href="/en-US/docs/Web/HTTP/Headers/Accept"><code>Accept</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Accept-CH"><code>Accept-CH</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Accept-Encoding"><code>Accept-Encoding</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Accept-Language"><code>Accept-Language</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Accept-Patch"><code>Accept-Patch</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Accept-Post"><code>Accept-Post</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Accept-Ranges"><code>Accept-Ranges</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Credentials"><code>Access-Control-Allow-Credentials</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Headers"><code>Access-Control-Allow-Headers</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Methods"><code>Access-Control-Allow-Methods</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Origin"><code>Access-Control-Allow-Origin</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Access-Control-Expose-Headers"><code>Access-Control-Expose-Headers</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Access-Control-Max-Age"><code>Access-Control-Max-Age</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Access-Control-Request-Headers"><code>Access-Control-Request-Headers</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Access-Control-Request-Method"><code>Access-Control-Request-Method</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Age"><code>Age</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Allow"><code>Allow</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Alt-Svc"><code>Alt-Svc</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Alt-Used"><code>Alt-Used</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Attribution-Reporting-Eligible"><code>Attribution-Reporting-Eligible</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Attribution-Reporting-Register-Source"><code>Attribution-Reporting-Register-Source</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Attribution-Reporting-Register-Trigger"><code>Attribution-Reporting-Register-Trigger</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Authorization"><code>Authorization</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Cache-Control"><code>Cache-Control</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Clear-Site-Data"><code>Clear-Site-Data</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Connection"><code>Connection</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Digest"><code>Content-Digest</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Disposition"><code>Content-Disposition</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-DPR"><code>Content-DPR</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Encoding"><code>Content-Encoding</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Language"><code>Content-Language</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Length"><code>Content-Length</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Location"><code>Content-Location</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Range"><code>Content-Range</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy"><code>Content-Security-Policy</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy-Report-Only"><code>Content-Security-Policy-Report-Only</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Type"><code>Content-Type</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Cookie"><code>Cookie</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Critical-CH"><code>Critical-CH</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Cross-Origin-Embedder-Policy"><code>Cross-Origin-Embedder-Policy</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Cross-Origin-Opener-Policy"><code>Cross-Origin-Opener-Policy</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Cross-Origin-Resource-Policy"><code>Cross-Origin-Resource-Policy</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Date"><code>Date</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Device-Memory"><code>Device-Memory</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Digest"><code>Digest</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/DNT"><code>DNT</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Downlink"><code>Downlink</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/DPR"><code>DPR</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Early-Data"><code>Early-Data</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/ECT"><code>ECT</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/ETag"><code>ETag</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Expect"><code>Expect</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Expect-CT"><code>Expect-CT</code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Expires"><code>Expires</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Forwarded"><code>Forwarded</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/From"><code>From</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Host"><code>Host</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/If-Match"><code>If-Match</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/If-Modified-Since"><code>If-Modified-Since</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/If-None-Match"><code>If-None-Match</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/If-Range"><code>If-Range</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/If-Unmodified-Since"><code>If-Unmodified-Since</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Keep-Alive"><code>Keep-Alive</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Last-Modified"><code>Last-Modified</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Link"><code>Link</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Location"><code>Location</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Max-Forwards"><code>Max-Forwards</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/NEL"><code>NEL</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/No-Vary-Search"><code>No-Vary-Search</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Observe-Browsing-Topics"><code>Observe-Browsing-Topics</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Origin"><code>Origin</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Origin-Agent-Cluster"><code>Origin-Agent-Cluster</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy"><code>Permissions-Policy</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Pragma"><code>Pragma</code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Priority"><code>Priority</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Proxy-Authenticate"><code>Proxy-Authenticate</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Proxy-Authorization"><code>Proxy-Authorization</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Range"><code>Range</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Referer"><code>Referer</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Referrer-Policy"><code>Referrer-Policy</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Refresh"><code>Refresh</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Report-To"><code>Report-To</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Reporting-Endpoints"><code>Reporting-Endpoints</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Repr-Digest"><code>Repr-Digest</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Retry-After"><code>Retry-After</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/RTT"><code>RTT</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Save-Data"><code>Save-Data</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-Browsing-Topics"><code>Sec-Browsing-Topics</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-CH-Prefers-Color-Scheme"><code>Sec-CH-Prefers-Color-Scheme</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-CH-Prefers-Reduced-Motion"><code>Sec-CH-Prefers-Reduced-Motion</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-CH-Prefers-Reduced-Transparency"><code>Sec-CH-Prefers-Reduced-Transparency</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-CH-UA"><code>Sec-CH-UA</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Arch"><code>Sec-CH-UA-Arch</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Bitness"><code>Sec-CH-UA-Bitness</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Full-Version"><code>Sec-CH-UA-Full-Version</code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Full-Version-List"><code>Sec-CH-UA-Full-Version-List</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Mobile"><code>Sec-CH-UA-Mobile</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Model"><code>Sec-CH-UA-Model</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Platform"><code>Sec-CH-UA-Platform</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Platform-Version"><code>Sec-CH-UA-Platform-Version</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-Fetch-Dest"><code>Sec-Fetch-Dest</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-Fetch-Mode"><code>Sec-Fetch-Mode</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-Fetch-Site"><code>Sec-Fetch-Site</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-Fetch-User"><code>Sec-Fetch-User</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-GPC"><code>Sec-GPC</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-Purpose"><code>Sec-Purpose</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-WebSocket-Accept"><code>Sec-WebSocket-Accept</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-WebSocket-Extensions"><code>Sec-WebSocket-Extensions</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-WebSocket-Key"><code>Sec-WebSocket-Key</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-WebSocket-Protocol"><code>Sec-WebSocket-Protocol</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Sec-WebSocket-Version"><code>Sec-WebSocket-Version</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Server"><code>Server</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Server-Timing"><code>Server-Timing</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Service-Worker-Navigation-Preload"><code>Service-Worker-Navigation-Preload</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Set-Cookie"><code>Set-Cookie</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Set-Login"><code>Set-Login</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/SourceMap"><code>SourceMap</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Speculation-Rules"><code>Speculation-Rules</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Strict-Transport-Security"><code>Strict-Transport-Security</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Supports-Loading-Mode"><code>Supports-Loading-Mode</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/TE"><code>TE</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Timing-Allow-Origin"><code>Timing-Allow-Origin</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Tk"><code>Tk</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Trailer"><code>Trailer</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Transfer-Encoding"><code>Transfer-Encoding</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Upgrade"><code>Upgrade</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Upgrade-Insecure-Requests"><code>Upgrade-Insecure-Requests</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/User-Agent"><code>User-Agent</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Vary"><code>Vary</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Via"><code>Via</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Viewport-Width"><code>Viewport-Width</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Want-Content-Digest"><code>Want-Content-Digest</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Want-Digest"><code>Want-Digest</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Want-Repr-Digest"><code>Want-Repr-Digest</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Warning"><code>Warning</code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Width"><code>Width</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/WWW-Authenticate"><code>WWW-Authenticate</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/X-Content-Type-Options"><code>X-Content-Type-Options</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/X-DNS-Prefetch-Control"><code>X-DNS-Prefetch-Control</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/X-Forwarded-For"><code>X-Forwarded-For</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/X-Forwarded-Host"><code>X-Forwarded-Host</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/X-Forwarded-Proto"><code>X-Forwarded-Proto</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/X-Frame-Options"><code>X-Frame-Options</code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/X-XSS-Protection"><code>X-XSS-Protection</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr></li></ol> </details> </li> <li class="toggle"> <details> <summary>HTTP request methods</summary> <ol><li><a href="/en-US/docs/Web/HTTP/Methods/CONNECT"><code>CONNECT</code></a></li><li><a href="/en-US/docs/Web/HTTP/Methods/DELETE"><code>DELETE</code></a></li><li><a href="/en-US/docs/Web/HTTP/Methods/GET"><code>GET</code></a></li><li><a href="/en-US/docs/Web/HTTP/Methods/HEAD"><code>HEAD</code></a></li><li><a href="/en-US/docs/Web/HTTP/Methods/OPTIONS"><code>OPTIONS</code></a></li><li><a href="/en-US/docs/Web/HTTP/Methods/PATCH"><code>PATCH</code></a></li><li><a href="/en-US/docs/Web/HTTP/Methods/POST"><code>POST</code></a></li><li><a href="/en-US/docs/Web/HTTP/Methods/PUT"><code>PUT</code></a></li><li><a href="/en-US/docs/Web/HTTP/Methods/TRACE"><code>TRACE</code></a></li></ol> </details> </li> <li class="toggle"> <details> <summary>HTTP response status codes</summary> <ol><li><a href="/en-US/docs/Web/HTTP/Status/100"><code>100 Continue</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/101"><code>101 Switching Protocols</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/102"><code>102 Processing</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/103"><code>103 Early Hints</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/200"><code>200 OK</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/201"><code>201 Created</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/202"><code>202 Accepted</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/203"><code>203 Non-Authoritative Information</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/204"><code>204 No Content</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/205"><code>205 Reset Content</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/206"><code>206 Partial Content</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/207"><code>207 Multi-Status</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/208"><code>208 Already Reported</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/226"><code>226 IM Used</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/300"><code>300 Multiple Choices</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/301"><code>301 Moved Permanently</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/302"><code>302 Found</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/303"><code>303 See Other</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/304"><code>304 Not Modified</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/307"><code>307 Temporary Redirect</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/308"><code>308 Permanent Redirect</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/400"><code>400 Bad Request</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/401"><code>401 Unauthorized</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/402"><code>402 Payment Required</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/403"><code>403 Forbidden</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/404"><code>404 Not Found</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/405"><code>405 Method Not Allowed</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/406"><code>406 Not Acceptable</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/407"><code>407 Proxy Authentication Required</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/408"><code>408 Request Timeout</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/409"><code>409 Conflict</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/410"><code>410 Gone</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/411"><code>411 Length Required</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/412"><code>412 Precondition Failed</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/413"><code>413 Content Too Large</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/414"><code>414 URI Too Long</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/415"><code>415 Unsupported Media Type</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/416"><code>416 Range Not Satisfiable</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/417"><code>417 Expectation Failed</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/418"><code>418 I'm a teapot</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/421"><code>421 Misdirected Request</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/422"><code>422 Unprocessable Content</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/423"><code>423 Locked</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/424"><code>424 Failed Dependency</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/425"><code>425 Too Early</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/426"><code>426 Upgrade Required</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/428"><code>428 Precondition Required</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/429"><code>429 Too Many Requests</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/431"><code>431 Request Header Fields Too Large</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/451"><code>451 Unavailable For Legal Reasons</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/500"><code>500 Internal Server Error</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/501"><code>501 Not Implemented</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/502"><code>502 Bad Gateway</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/503"><code>503 Service Unavailable</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/504"><code>504 Gateway Timeout</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/505"><code>505 HTTP Version Not Supported</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/506"><code>506 Variant Also Negotiates</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/507"><code>507 Insufficient Storage</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/508"><code>508 Loop Detected</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/510"><code>510 Not Extended</code></a></li><li><a href="/en-US/docs/Web/HTTP/Status/511"><code>511 Network Authentication Required</code></a></li></ol> </details> </li> <li class="toggle"> <details> <summary>CSP directives</summary> <ol><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/base-uri"><code>CSP: base-uri</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/block-all-mixed-content"><code>CSP: block-all-mixed-content</code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/child-src"><code>CSP: child-src</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/connect-src"><code>CSP: connect-src</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/default-src"><code>CSP: default-src</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/fenced-frame-src"><code>CSP: fenced-frame-src</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/font-src"><code>CSP: font-src</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/form-action"><code>CSP: form-action</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/frame-ancestors"><code>CSP: frame-ancestors</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/frame-src"><code>CSP: frame-src</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/img-src"><code>CSP: img-src</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/manifest-src"><code>CSP: manifest-src</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/media-src"><code>CSP: media-src</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/object-src"><code>CSP: object-src</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/prefetch-src"><code>CSP: prefetch-src</code></a><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/report-to"><code>CSP: report-to</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/report-uri"><code>CSP: report-uri</code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/require-trusted-types-for"><code>CSP: require-trusted-types-for</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/sandbox"><code>CSP: sandbox</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/script-src"><code>CSP: script-src</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/script-src-attr"><code>CSP: script-src-attr</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/script-src-elem"><code>CSP: script-src-elem</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/style-src"><code>CSP: style-src</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/style-src-attr"><code>CSP: style-src-attr</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/style-src-elem"><code>CSP: style-src-elem</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/trusted-types"><code>CSP: trusted-types</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/upgrade-insecure-requests"><code>CSP: upgrade-insecure-requests</code></a></li><li><a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/worker-src"><code>CSP: worker-src</code></a></li></ol> </details> </li> <li class="toggle"> <details> <summary>CORS errors</summary> <ol><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSDisabled">Reason: CORS disabled</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSAllowOriginNotMatchingOrigin">Reason: CORS header 'Access-Control-Allow-Origin' does not match 'xyz'</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSMissingAllowOrigin">Reason: CORS header 'Access-Control-Allow-Origin' missing</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSOriginHeaderNotAdded">Reason: CORS header 'Origin' cannot be added</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSPreflightDidNotSucceed">Reason: CORS preflight channel did not succeed</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSDidNotSucceed">Reason: CORS request did not succeed</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSExternalRedirectNotAllowed">Reason: CORS request external redirect not allowed</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSRequestNotHttp">Reason: CORS request not HTTP</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSNotSupportingCredentials">Reason: Credential is not supported if the CORS header 'Access-Control-Allow-Origin' is '*'</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSMethodNotFound">Reason: Did not find method in CORS header 'Access-Control-Allow-Methods'</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSMIssingAllowCredentials">Reason: expected 'true' in CORS header 'Access-Control-Allow-Credentials'</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSInvalidAllowHeader">Reason: invalid token 'xyz' in CORS header 'Access-Control-Allow-Headers'</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSInvalidAllowMethod">Reason: invalid token 'xyz' in CORS header 'Access-Control-Allow-Methods'</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSMissingAllowHeaderFromPreflight">Reason: missing token 'xyz' in CORS header 'Access-Control-Allow-Headers' from CORS preflight channel</a></li><li><a href="/en-US/docs/Web/HTTP/CORS/Errors/CORSMultipleAllowOriginNotAllowed">Reason: Multiple CORS header 'Access-Control-Allow-Origin' not allowed</a></li></ol> </details> </li> <li class="toggle"> <details> <summary>Permissions-Policy directives</summary> <ol><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/accelerometer">Permissions-Policy: accelerometer</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/ambient-light-sensor">Permissions-Policy: ambient-light-sensor</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/attribution-reporting">Permissions-Policy: attribution-reporting</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/autoplay">Permissions-Policy: autoplay</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/bluetooth">Permissions-Policy: bluetooth</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/browsing-topics">Permissions-Policy: browsing-topics</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/camera">Permissions-Policy: camera</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/compute-pressure">Permissions-Policy: compute-pressure</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/display-capture">Permissions-Policy: display-capture</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/document-domain">Permissions-Policy: document-domain</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/encrypted-media">Permissions-Policy: encrypted-media</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/fullscreen">Permissions-Policy: fullscreen</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/gamepad">Permissions-Policy: gamepad</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/geolocation">Permissions-Policy: geolocation</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/gyroscope">Permissions-Policy: gyroscope</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/hid">Permissions-Policy: hid</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/identity-credentials-get">Permissions-Policy: identity-credentials-get</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/idle-detection">Permissions-Policy: idle-detection</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/local-fonts">Permissions-Policy: local-fonts</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/magnetometer">Permissions-Policy: magnetometer</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/microphone">Permissions-Policy: microphone</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/midi">Permissions-Policy: midi</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/otp-credentials">Permissions-Policy: otp-credentials</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/payment">Permissions-Policy: payment</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/picture-in-picture">Permissions-Policy: picture-in-picture</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/publickey-credentials-create">Permissions-Policy: publickey-credentials-create</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/publickey-credentials-get">Permissions-Policy: publickey-credentials-get</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/screen-wake-lock">Permissions-Policy: screen-wake-lock</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/serial">Permissions-Policy: serial</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/speaker-selection">Permissions-Policy: speaker-selection</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/storage-access">Permissions-Policy: storage-access</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/usb">Permissions-Policy: usb</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/web-share">Permissions-Policy: web-share</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/window-management">Permissions-Policy: window-management</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTTP/Headers/Permissions-Policy/xr-spatial-tracking">Permissions-Policy: xr-spatial-tracking</a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li></ol> </details> </li> <li><a href="/en-US/docs/Web/HTTP/Resources_and_specifications">HTTP resources and specifications</a></li> </ol> </div></div><section class="place side"></section></nav></aside><div class="toc-container"><aside class="toc"><nav><div class="document-toc-container"><section class="document-toc"><header><h2 class="document-toc-heading">In this article</h2></header><ul class="document-toc-list"><li class="document-toc-item "><a class="document-toc-link" href="#references">References</a></li><li class="document-toc-item "><a class="document-toc-link" href="#http_guides">HTTP guides</a></li><li class="document-toc-item "><a class="document-toc-link" href="#tools_resources">Tools & resources</a></li></ul></section></div></nav></aside><section class="place side"></section></div></div><main id="content" class="main-content "><article class="main-page-content" lang="en-US"><header><h1>HTTP</h1></header><div class="section-content"><p> <strong><em>Hypertext Transfer Protocol (HTTP)</em></strong> is an <a href="https://en.wikipedia.org/wiki/Application_Layer" class="external" target="_blank">application-layer</a> protocol for transmitting hypermedia documents, such as HTML. It was designed for communication between web browsers and web servers, but it can also be used for other purposes, such as machine-to-machine communication, programmatic access to APIs, and more. </p> <p> HTTP follows a classical <a href="https://en.wikipedia.org/wiki/Client%E2%80%93server_model" class="external" target="_blank">client-server model</a>, with a client opening a connection to make a request, then waiting until it receives a response from the server. HTTP is a <a href="https://en.wikipedia.org/wiki/Stateless_protocol" class="external" target="_blank">stateless protocol</a>, meaning that the server does not keep any session data between two requests, although the later addition of <a href="/en-US/docs/Web/HTTP/Cookies">cookies</a> adds state to some client-server interactions. </p></div><section aria-labelledby="references"><h2 id="references"><a href="#references">References</a></h2><div class="section-content"><p>The HTTP reference documentation contains detailed information about headers, request methods, status responses, and lists relevant specifications and standards documents.</p> <dl> <dt id="http_headers"><a href="/en-US/docs/Web/HTTP/Headers">HTTP headers</a></dt> <dd> <p>Message headers are used to send metadata about a resource or a HTTP message, and to describe the behavior of the client or the server.</p> </dd> <dt id="http_request_methods"><a href="/en-US/docs/Web/HTTP/Methods">HTTP request methods</a></dt> <dd> <p> Request methods indicate the purpose of the request and what is expected if the request is successful. The most common methods are <a href="/en-US/docs/Web/HTTP/Methods/GET"><code>GET</code></a> and <a href="/en-US/docs/Web/HTTP/Methods/POST"><code>POST</code></a> for retrieving and sending data to servers, respectively, but there are other methods which serve different purposes. </p> </dd> <dt id="http_response_status_codes"><a href="/en-US/docs/Web/HTTP/Status">HTTP response status codes</a></dt> <dd> <p> Response status codes indicate the outcome of a specific HTTP request. Responses are grouped in five classes: informational, successful, redirections, client errors, and server errors. </p> </dd> <dt id="http_resources_and_specifications"><a href="/en-US/docs/Web/HTTP/Resources_and_specifications">HTTP resources and specifications</a></dt> <dd> <p>This page lists relevant resources about HTTP since it was first specified in the early 1990s.</p> </dd> </dl></div></section><section aria-labelledby="http_guides"><h2 id="http_guides"><a href="#http_guides">HTTP guides</a></h2><div class="section-content"><p> HTTP is an extensible protocol that relies on concepts like resources and Uniform Resource Identifiers (URIs), a simple message structure, and client-server communication model. On top of these concepts, numerous extensions have been developed over the years that add functionality and updated semantics, including additional HTTP methods and headers. </p> <p> The guides below are listed in order from general overviews to specialized, use-case-driven topics. Beginners are encouraged to start with the foundational guides before exploring more focused articles. </p> <dl> <dt id="overview_of_http"><a href="/en-US/docs/Web/HTTP/Overview">Overview of HTTP</a></dt> <dd> <p>The basic features of HTTP, what it can do, its intended use in web architecture, and its position in the protocol stack.</p> </dd> <dt id="a_typical_http_session"><a href="/en-US/docs/Web/HTTP/Session">A typical HTTP session</a></dt> <dd> <p>Describes the flow of an HTTP session, from establishing a connection, sending a request, to receiving a response.</p> </dd> <dt id="http_messages"><a href="/en-US/docs/Web/HTTP/Messages">HTTP messages</a></dt> <dd> <p> HTTP messages transmitted as requests and responses have a defined structure. This article describes this general structure, its purpose, and the different types of messages. </p> </dd> <dt id="uris"><a href="/en-US/docs/Web/URI">URIs</a></dt> <dd> <p>Uniform Resource Identifiers (URIs) are used to describe and locate resources on the web and are an essential component in HTTP requests.</p> </dd> <dt id="mime_types"><a href="/en-US/docs/Web/HTTP/MIME_types">MIME types</a></dt> <dd> <p> Since HTTP/1.0, different types of content can be transmitted. This article explains how this is accomplished using the <a href="/en-US/docs/Web/HTTP/Headers/Content-Type"><code>Content-Type</code></a> header and the MIME standard. A shortlist of common types used by web developers can be found in <a href="/en-US/docs/Web/HTTP/MIME_types/Common_types">Common MIME types</a>. </p> </dd> <dt id="compression_in_http"><a href="/en-US/docs/Web/HTTP/Compression">Compression in HTTP</a></dt> <dd> <p>Browsers and servers compress their messages before sending them over the network to reduce the amount of data that needs to be transmitted, improving transfer speed and bandwidth utilization.</p> </dd> <dt id="http_caching"><a href="/en-US/docs/Web/HTTP/Caching">HTTP caching</a></dt> <dd> <p> Caching is a highly important mechanism for delivering fast experiences on the Web and for efficient use of resources. This article describes different methods of caching and how to use HTTP headers to control them. </p> </dd> <dt id="http_authentication"><a href="/en-US/docs/Web/HTTP/Authentication">HTTP authentication</a></dt> <dd> <p> Authentication is a way to verify the identity of a client when making requests to a server. It ensures that only authorized users or systems can access certain resources. </p> </dd> <dt id="using_http_cookies"><a href="/en-US/docs/Web/HTTP/Cookies">Using HTTP cookies</a></dt> <dd> <p> Although HTTP is a stateless protocol, a server can send a <a href="/en-US/docs/Web/HTTP/Headers/Set-Cookie"><code>Set-Cookie</code></a> header with the response. The client then returns the cookie's value with every subsequent request to the server in the form of a <a href="/en-US/docs/Web/HTTP/Headers/Cookie"><code>Cookie</code></a> request header. This adds the ability to store and exchange a small amount of data which effectively adds state to some client-server interactions. </p> </dd> <dt id="redirections_in_http"><a href="/en-US/docs/Web/HTTP/Redirections">Redirections in HTTP</a></dt> <dd> <p> URL redirection, also known as URL forwarding, is a technique to give more than one URL address to a page, a form, a whole website, or a web application. HTTP has a special kind of response, called a HTTP redirect, for this operation. </p> </dd> <dt id="http_conditional_requests"><a href="/en-US/docs/Web/HTTP/Conditional_requests">HTTP conditional requests</a></dt> <dd> <p> In conditional requests, the outcome of a request depends on the value of a validator in the request. This method is used heavily in <a href="/en-US/docs/Web/HTTP/Caching">caching</a> and use cases such as resuming a download, preventing lost updates when modifying a document on the server, and more. </p> </dd> <dt id="http_range_requests"><a href="/en-US/docs/Web/HTTP/Range_requests">HTTP range requests</a></dt> <dd> <p> A range request asks the server to send a specific part (or parts) of a resource back to a client instead of the full resource. Range requests are useful for cases when a client knows they need only part of a large file, or for cases where an application allows the user to pause and resume a download. </p> </dd> <dt id="content_negotiation"><a href="/en-US/docs/Web/HTTP/Content_negotiation">Content negotiation</a></dt> <dd> <p> HTTP defines a set of message headers, starting with <a href="/en-US/docs/Web/HTTP/Headers/Accept"><code>Accept</code></a> as a way for a browser to announce the format, language, or encoding it prefers. This article explains how this advertisement happens, how the server is expected to react, and how it chooses the most adequate response to a request. </p> </dd> <dt id="connection_management_in_http1.x"><a href="/en-US/docs/Web/HTTP/Connection_management_in_HTTP_1.x">Connection management in HTTP/1.x</a></dt> <dd> <p> HTTP/1.1 was the first version of HTTP to support persistent connections and pipelining. This article explains both concepts, including the pros and cons of each. </p> </dd> <dt id="evolution_of_http"><a href="/en-US/docs/Web/HTTP/Evolution_of_HTTP">Evolution of HTTP</a></dt> <dd> <p> HTTP was created in the early 1990s and has been extended several times. This article goes through its history and describes HTTP/0.9, HTTP/1.0, HTTP/1.1, through HTTP/2 and HTTP/3, as well as novelties introduced over the years. </p> </dd> <dt id="protocol_upgrade_mechanism"><a href="/en-US/docs/Web/HTTP/Protocol_upgrade_mechanism">Protocol upgrade mechanism</a></dt> <dd> <p> HTTP/1.1 provides a mechanism to upgrade an already-established connection to a different protocol using the <a href="/en-US/docs/Web/HTTP/Headers/Upgrade"><code>Upgrade</code></a> header. A client can upgrade a connection from HTTP/1.1 to HTTP/2, or an HTTP(S) connection to a <a href="/en-US/docs/Web/API/WebSocket">WebSocket</a> (<code>ws</code> / <code>wss</code>). </p> </dd> <dt id="proxy_servers_and_tunneling"><a href="/en-US/docs/Web/HTTP/Proxy_servers_and_tunneling">Proxy servers and tunneling</a></dt> <dd> <p> A proxy can be on the user's local computer, or anywhere between the user's computer and a destination server on the Internet. This page outlines some basics about proxies and introduces a few configuration options. </p> </dd> <dt id="http_client_hints"><a href="/en-US/docs/Web/HTTP/Client_hints">HTTP Client hints</a></dt> <dd> <p> Client Hints are a set of response headers that a server can use to proactively request information from a client about the device, network, user, and user-agent-specific preferences. The server can then determine which resources to send, based on the information that the client chooses to provide. </p> </dd> <dt id="network_error_logging"><a href="/en-US/docs/Web/HTTP/Network_Error_Logging">Network Error Logging</a> <abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></dt> <dd> <p> Network Error Logging is a mechanism that can be configured via the <code>NEL</code> HTTP response header. This experimental header allows websites and applications to opt-in to receive reports about failed (or even successful) network fetches from supporting browsers. </p> </dd> <dt id="browser_detection_using_the_user_agent"><a href="/en-US/docs/Web/HTTP/Browser_detection_using_the_user_agent">Browser detection using the user agent</a></dt> <dd> <p> It's very rarely a good idea to use user agent sniffing to detect a browser, but there are edge cases that require it. This document will guide you in doing this as correctly as possible when this is necessary, with an emphasis on considerations to make before embarking on this route. </p> </dd> <dt id="configuring_servers_for_ogg_media"><a href="/en-US/docs/Web/HTTP/Configuring_servers_for_Ogg_media">Configuring servers for Ogg media</a></dt> <dd> <p> This guide covers a few server configuration changes that may be necessary for your web server to correctly serve Ogg media files. This information may also be useful if you encounter other media types your server isn't already configured to recognize. </p> </dd> </dl></div></section><section aria-labelledby="security_and_privacy"><h3 id="security_and_privacy"><a href="#security_and_privacy">Security and privacy</a></h3><div class="section-content"><dl> <dt id="mozilla_web_security_guidelines"><a href="https://infosec.mozilla.org/guidelines/web_security" class="external" target="_blank">Mozilla web security guidelines</a></dt> <dd> <p>A collection of tips to help operational teams with creating secure web applications.</p> </dd> <dt id="permissions_policy"><a href="/en-US/docs/Web/HTTP/Permissions_Policy">Permissions Policy</a></dt> <dd> <p> Permissions Policy provides mechanisms for web developers to explicitly declare what functionality can and cannot be used on a website. You define a set of "policies" that restrict what APIs the site's code can access or modify the browser's default behavior for certain features. </p> </dd> <dt id="cross-origin_resource_sharing_cors"><a href="/en-US/docs/Web/HTTP/CORS">Cross-Origin Resource Sharing (CORS)</a></dt> <dd> <p> Cross-site HTTP requests are requests for resources from a different domain than that of the resource making the request. Web pages today very commonly load cross-site resources, for example, a page 'Domain A' (<code>http://domaina.example/</code>) requests an image on 'Domain B' (<code>http://domainb.foo/image.jpg</code>) via the <code>img</code> element. CORS allows web developers to control how their site reacts to cross-site requests. </p> </dd> <dt id="content_security_policy_csp"><a href="/en-US/docs/Web/HTTP/CSP">Content Security Policy (CSP)</a></dt> <dd> <p> CSP allows website administrators to use the <a href="/en-US/docs/Web/HTTP/Headers/Content-Security-Policy"><code>Content-Security-Policy</code></a> response header to control which resources the client is allowed to load for a given page. The CSP guide describes the overall Content Security Policy mechanism which helps detect and mitigate certain types of attacks, including Cross-Site Scripting (XSS) and data injection attacks. </p> </dd> <dt id="cross-origin_resource_policy_corp"><a href="/en-US/docs/Web/HTTP/Cross-Origin_Resource_Policy">Cross-Origin Resource Policy (CORP)</a></dt> <dd> <p>CORP lets websites and applications opt in to protection against specific requests from other origins (such as those issued with elements like <code><script></code> and <code><img></code>), to mitigate speculative side-channel attacks.</p> </dd> </dl></div></section><section aria-labelledby="tools_resources"><h2 id="tools_resources"><a href="#tools_resources">Tools & resources</a></h2><div class="section-content"><p>Helpful tools and resources for understanding and debugging HTTP.</p> <dl> <dt id="firefox_developer_tools"><a href="https://firefox-source-docs.mozilla.org/devtools-user/index.html" class="external" target="_blank">Firefox Developer Tools</a></dt> <dd> <p><a href="https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/index.html" class="external" target="_blank">Network monitor</a></p> </dd> <dt id="http_observatory"><a href="/en-US/observatory">HTTP Observatory</a></dt> <dd> <p>A project designed to help developers, system administrators, and security professionals configure their sites safely and securely.</p> </dd> <dt id="redbot"><a href="https://redbot.org/" class="external" target="_blank">RedBot</a></dt> <dd> <p>Tools to check your cache-related headers.</p> </dd> <dt id="nghttp2"><a href="https://github.com/nghttp2/nghttp2" class="external" target="_blank">nghttp2</a></dt> <dd> <p>An HTTP/2 client, server and proxy implementation written in C with load test and benchmarking tools and an HPACK encoder and decoder.</p> </dd> <dt id="curl"><a href="https://github.com/curl/curl" class="external" target="_blank">curl</a></dt> <dd> <p> A command-line tool for transferring data specified with URL syntax. Supports HTTP, HTTPS, WS, WSS, among many other protocols. </p> </dd> <dt id="how_browsers_work_2011"><a href="https://web.dev/articles/howbrowserswork" class="external" target="_blank">How Browsers Work (2011)</a></dt> <dd> <p>A very comprehensive article on browser internals and request flow through HTTP protocol.</p> </dd> </dl></div></section></article><aside class="article-footer"><div class="article-footer-inner"><div class="svg-container"><svg xmlns="http://www.w3.org/2000/svg" width="162" height="162" viewBox="0 0 162 162" fill="none" role="none"><mask id="b" fill="#fff"><path d="M97.203 47.04c8.113-7.886 18.004-13.871 28.906-17.492a78 78 0 0 1 33.969-3.39c11.443 1.39 22.401 5.295 32.024 11.411s17.656 14.28 23.476 23.86c5.819 9.579 9.269 20.318 10.083 31.385a69.85 69.85 0 0 1-5.387 32.44c-4.358 10.272-11.115 19.443-19.747 26.801-8.632 7.359-18.908 12.709-30.034 15.637l-6.17-21.698c7.666-2.017 14.746-5.703 20.694-10.773 5.948-5.071 10.603-11.389 13.606-18.467a48.14 48.14 0 0 0 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href=\"/en-US/docs/Web/HTTP/Caching\">HTTP caching</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Authentication\">HTTP authentication</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Cookies\">Using HTTP cookies</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Redirections\">Redirections in HTTP</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Conditional_requests\">HTTP conditional requests</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Range_requests\">HTTP range requests</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Content_negotiation\">Content negotiation</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Connection_management_in_HTTP_1.x\">Connection management in HTTP/1.x</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Evolution_of_HTTP\">Evolution of HTTP</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Protocol_upgrade_mechanism\">Protocol upgrade mechanism</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Proxy_servers_and_tunneling\">Proxy servers and tunneling</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Client_hints\">HTTP Client hints</a></li>\n <li class=\"toggle\">\n <details>\n <summary>Security and privacy</summary>\n <ol>\n <li><a href=\"/en-US/docs/Web/Security/Practical_implementation_guides\">Practical security implementation guides</a></li>\n <li><a href=\"/en-US/observatory\">HTTP Observatory</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Permissions_Policy\">Permissions Policy</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/CSP\">Content Security Policy (CSP)</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/CORS\">Cross-Origin Resource Sharing (CORS)</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Cross-Origin_Resource_Policy\">Cross-Origin Resource Policy (CORP)</a></li>\n <li><a href=\"/en-US/docs/Web/HTTP/Headers/Strict-Transport-Security\">Strict-Transport-Security</a></li>\n </ol>\n </details>\n </li>\n <li class=\"section no-link\">References</li>\n <li class=\"toggle\">\n <details>\n <summary>HTTP headers</summary>\n <ol><li><a href=\"/en-US/docs/Web/HTTP/Headers/Accept\"><code>Accept</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Accept-CH\"><code>Accept-CH</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Accept-Encoding\"><code>Accept-Encoding</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Accept-Language\"><code>Accept-Language</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Accept-Patch\"><code>Accept-Patch</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Accept-Post\"><code>Accept-Post</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Accept-Ranges\"><code>Accept-Ranges</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Credentials\"><code>Access-Control-Allow-Credentials</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Headers\"><code>Access-Control-Allow-Headers</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Methods\"><code>Access-Control-Allow-Methods</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Origin\"><code>Access-Control-Allow-Origin</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Access-Control-Expose-Headers\"><code>Access-Control-Expose-Headers</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Access-Control-Max-Age\"><code>Access-Control-Max-Age</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Access-Control-Request-Headers\"><code>Access-Control-Request-Headers</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Access-Control-Request-Method\"><code>Access-Control-Request-Method</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Age\"><code>Age</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Allow\"><code>Allow</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Alt-Svc\"><code>Alt-Svc</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Alt-Used\"><code>Alt-Used</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Attribution-Reporting-Eligible\"><code>Attribution-Reporting-Eligible</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Attribution-Reporting-Register-Source\"><code>Attribution-Reporting-Register-Source</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Attribution-Reporting-Register-Trigger\"><code>Attribution-Reporting-Register-Trigger</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Authorization\"><code>Authorization</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Cache-Control\"><code>Cache-Control</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Clear-Site-Data\"><code>Clear-Site-Data</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Connection\"><code>Connection</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Digest\"><code>Content-Digest</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Disposition\"><code>Content-Disposition</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-DPR\"><code>Content-DPR</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Encoding\"><code>Content-Encoding</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Language\"><code>Content-Language</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Length\"><code>Content-Length</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Location\"><code>Content-Location</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Range\"><code>Content-Range</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy\"><code>Content-Security-Policy</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy-Report-Only\"><code>Content-Security-Policy-Report-Only</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Type\"><code>Content-Type</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Cookie\"><code>Cookie</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Critical-CH\"><code>Critical-CH</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Cross-Origin-Embedder-Policy\"><code>Cross-Origin-Embedder-Policy</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Cross-Origin-Opener-Policy\"><code>Cross-Origin-Opener-Policy</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Cross-Origin-Resource-Policy\"><code>Cross-Origin-Resource-Policy</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Date\"><code>Date</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Device-Memory\"><code>Device-Memory</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Digest\"><code>Digest</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/DNT\"><code>DNT</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Downlink\"><code>Downlink</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/DPR\"><code>DPR</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Early-Data\"><code>Early-Data</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/ECT\"><code>ECT</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/ETag\"><code>ETag</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Expect\"><code>Expect</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Expect-CT\"><code>Expect-CT</code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Expires\"><code>Expires</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Forwarded\"><code>Forwarded</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/From\"><code>From</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Host\"><code>Host</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/If-Match\"><code>If-Match</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/If-Modified-Since\"><code>If-Modified-Since</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/If-None-Match\"><code>If-None-Match</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/If-Range\"><code>If-Range</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/If-Unmodified-Since\"><code>If-Unmodified-Since</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Keep-Alive\"><code>Keep-Alive</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Last-Modified\"><code>Last-Modified</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Link\"><code>Link</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Location\"><code>Location</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Max-Forwards\"><code>Max-Forwards</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/NEL\"><code>NEL</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/No-Vary-Search\"><code>No-Vary-Search</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Observe-Browsing-Topics\"><code>Observe-Browsing-Topics</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Origin\"><code>Origin</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Origin-Agent-Cluster\"><code>Origin-Agent-Cluster</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy\"><code>Permissions-Policy</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Pragma\"><code>Pragma</code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Priority\"><code>Priority</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Proxy-Authenticate\"><code>Proxy-Authenticate</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Proxy-Authorization\"><code>Proxy-Authorization</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Range\"><code>Range</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Referer\"><code>Referer</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Referrer-Policy\"><code>Referrer-Policy</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Refresh\"><code>Refresh</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Report-To\"><code>Report-To</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Reporting-Endpoints\"><code>Reporting-Endpoints</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Repr-Digest\"><code>Repr-Digest</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Retry-After\"><code>Retry-After</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/RTT\"><code>RTT</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Save-Data\"><code>Save-Data</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-Browsing-Topics\"><code>Sec-Browsing-Topics</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-CH-Prefers-Color-Scheme\"><code>Sec-CH-Prefers-Color-Scheme</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-CH-Prefers-Reduced-Motion\"><code>Sec-CH-Prefers-Reduced-Motion</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-CH-Prefers-Reduced-Transparency\"><code>Sec-CH-Prefers-Reduced-Transparency</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-CH-UA\"><code>Sec-CH-UA</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Arch\"><code>Sec-CH-UA-Arch</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Bitness\"><code>Sec-CH-UA-Bitness</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Full-Version\"><code>Sec-CH-UA-Full-Version</code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Full-Version-List\"><code>Sec-CH-UA-Full-Version-List</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Mobile\"><code>Sec-CH-UA-Mobile</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Model\"><code>Sec-CH-UA-Model</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Platform\"><code>Sec-CH-UA-Platform</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-CH-UA-Platform-Version\"><code>Sec-CH-UA-Platform-Version</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-Fetch-Dest\"><code>Sec-Fetch-Dest</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-Fetch-Mode\"><code>Sec-Fetch-Mode</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-Fetch-Site\"><code>Sec-Fetch-Site</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-Fetch-User\"><code>Sec-Fetch-User</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-GPC\"><code>Sec-GPC</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-Purpose\"><code>Sec-Purpose</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-WebSocket-Accept\"><code>Sec-WebSocket-Accept</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-WebSocket-Extensions\"><code>Sec-WebSocket-Extensions</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-WebSocket-Key\"><code>Sec-WebSocket-Key</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-WebSocket-Protocol\"><code>Sec-WebSocket-Protocol</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Sec-WebSocket-Version\"><code>Sec-WebSocket-Version</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Server\"><code>Server</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Server-Timing\"><code>Server-Timing</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Service-Worker-Navigation-Preload\"><code>Service-Worker-Navigation-Preload</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Set-Cookie\"><code>Set-Cookie</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Set-Login\"><code>Set-Login</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/SourceMap\"><code>SourceMap</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Speculation-Rules\"><code>Speculation-Rules</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Strict-Transport-Security\"><code>Strict-Transport-Security</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Supports-Loading-Mode\"><code>Supports-Loading-Mode</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/TE\"><code>TE</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Timing-Allow-Origin\"><code>Timing-Allow-Origin</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Tk\"><code>Tk</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Trailer\"><code>Trailer</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Transfer-Encoding\"><code>Transfer-Encoding</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Upgrade\"><code>Upgrade</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Upgrade-Insecure-Requests\"><code>Upgrade-Insecure-Requests</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/User-Agent\"><code>User-Agent</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Vary\"><code>Vary</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Via\"><code>Via</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Viewport-Width\"><code>Viewport-Width</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Want-Content-Digest\"><code>Want-Content-Digest</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Want-Digest\"><code>Want-Digest</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Want-Repr-Digest\"><code>Want-Repr-Digest</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Warning\"><code>Warning</code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Width\"><code>Width</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/WWW-Authenticate\"><code>WWW-Authenticate</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/X-Content-Type-Options\"><code>X-Content-Type-Options</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/X-DNS-Prefetch-Control\"><code>X-DNS-Prefetch-Control</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/X-Forwarded-For\"><code>X-Forwarded-For</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/X-Forwarded-Host\"><code>X-Forwarded-Host</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/X-Forwarded-Proto\"><code>X-Forwarded-Proto</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/X-Frame-Options\"><code>X-Frame-Options</code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/X-XSS-Protection\"><code>X-XSS-Protection</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr></li></ol>\n </details>\n </li>\n <li class=\"toggle\">\n <details>\n <summary>HTTP request methods</summary>\n <ol><li><a href=\"/en-US/docs/Web/HTTP/Methods/CONNECT\"><code>CONNECT</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Methods/DELETE\"><code>DELETE</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Methods/GET\"><code>GET</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Methods/HEAD\"><code>HEAD</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Methods/OPTIONS\"><code>OPTIONS</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Methods/PATCH\"><code>PATCH</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Methods/POST\"><code>POST</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Methods/PUT\"><code>PUT</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Methods/TRACE\"><code>TRACE</code></a></li></ol>\n </details>\n </li>\n <li class=\"toggle\">\n <details>\n <summary>HTTP response status codes</summary>\n <ol><li><a href=\"/en-US/docs/Web/HTTP/Status/100\"><code>100 Continue</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/101\"><code>101 Switching Protocols</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/102\"><code>102 Processing</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/103\"><code>103 Early Hints</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/200\"><code>200 OK</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/201\"><code>201 Created</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/202\"><code>202 Accepted</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/203\"><code>203 Non-Authoritative Information</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/204\"><code>204 No Content</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/205\"><code>205 Reset Content</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/206\"><code>206 Partial Content</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/207\"><code>207 Multi-Status</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/208\"><code>208 Already Reported</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/226\"><code>226 IM Used</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/300\"><code>300 Multiple Choices</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/301\"><code>301 Moved Permanently</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/302\"><code>302 Found</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/303\"><code>303 See Other</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/304\"><code>304 Not Modified</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/307\"><code>307 Temporary Redirect</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/308\"><code>308 Permanent Redirect</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/400\"><code>400 Bad Request</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/401\"><code>401 Unauthorized</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/402\"><code>402 Payment Required</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/403\"><code>403 Forbidden</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/404\"><code>404 Not Found</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/405\"><code>405 Method Not Allowed</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/406\"><code>406 Not Acceptable</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/407\"><code>407 Proxy Authentication Required</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/408\"><code>408 Request Timeout</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/409\"><code>409 Conflict</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/410\"><code>410 Gone</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/411\"><code>411 Length Required</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/412\"><code>412 Precondition Failed</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/413\"><code>413 Content Too Large</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/414\"><code>414 URI Too Long</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/415\"><code>415 Unsupported Media Type</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/416\"><code>416 Range Not Satisfiable</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/417\"><code>417 Expectation Failed</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/418\"><code>418 I'm a teapot</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/421\"><code>421 Misdirected Request</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/422\"><code>422 Unprocessable Content</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/423\"><code>423 Locked</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/424\"><code>424 Failed Dependency</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/425\"><code>425 Too Early</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/426\"><code>426 Upgrade Required</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/428\"><code>428 Precondition Required</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/429\"><code>429 Too Many Requests</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/431\"><code>431 Request Header Fields Too Large</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/451\"><code>451 Unavailable For Legal Reasons</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/500\"><code>500 Internal Server Error</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/501\"><code>501 Not Implemented</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/502\"><code>502 Bad Gateway</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/503\"><code>503 Service Unavailable</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/504\"><code>504 Gateway Timeout</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/505\"><code>505 HTTP Version Not Supported</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/506\"><code>506 Variant Also Negotiates</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/507\"><code>507 Insufficient Storage</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/508\"><code>508 Loop Detected</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/510\"><code>510 Not Extended</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Status/511\"><code>511 Network Authentication Required</code></a></li></ol>\n </details>\n </li>\n <li class=\"toggle\">\n <details>\n <summary>CSP directives</summary>\n <ol><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/base-uri\"><code>CSP: base-uri</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/block-all-mixed-content\"><code>CSP: block-all-mixed-content</code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/child-src\"><code>CSP: child-src</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/connect-src\"><code>CSP: connect-src</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/default-src\"><code>CSP: default-src</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/fenced-frame-src\"><code>CSP: fenced-frame-src</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/font-src\"><code>CSP: font-src</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/form-action\"><code>CSP: form-action</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/frame-ancestors\"><code>CSP: frame-ancestors</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/frame-src\"><code>CSP: frame-src</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/img-src\"><code>CSP: img-src</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/manifest-src\"><code>CSP: manifest-src</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/media-src\"><code>CSP: media-src</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/object-src\"><code>CSP: object-src</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/prefetch-src\"><code>CSP: prefetch-src</code></a><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/report-to\"><code>CSP: report-to</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/report-uri\"><code>CSP: report-uri</code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/require-trusted-types-for\"><code>CSP: require-trusted-types-for</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/sandbox\"><code>CSP: sandbox</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/script-src\"><code>CSP: script-src</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/script-src-attr\"><code>CSP: script-src-attr</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/script-src-elem\"><code>CSP: script-src-elem</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/style-src\"><code>CSP: style-src</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/style-src-attr\"><code>CSP: style-src-attr</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/style-src-elem\"><code>CSP: style-src-elem</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/trusted-types\"><code>CSP: trusted-types</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/upgrade-insecure-requests\"><code>CSP: upgrade-insecure-requests</code></a></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/worker-src\"><code>CSP: worker-src</code></a></li></ol>\n </details>\n </li>\n <li class=\"toggle\">\n <details>\n <summary>CORS errors</summary>\n <ol><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSDisabled\">Reason: CORS disabled</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSAllowOriginNotMatchingOrigin\">Reason: CORS header 'Access-Control-Allow-Origin' does not match 'xyz'</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSMissingAllowOrigin\">Reason: CORS header 'Access-Control-Allow-Origin' missing</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSOriginHeaderNotAdded\">Reason: CORS header 'Origin' cannot be added</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSPreflightDidNotSucceed\">Reason: CORS preflight channel did not succeed</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSDidNotSucceed\">Reason: CORS request did not succeed</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSExternalRedirectNotAllowed\">Reason: CORS request external redirect not allowed</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSRequestNotHttp\">Reason: CORS request not HTTP</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSNotSupportingCredentials\">Reason: Credential is not supported if the CORS header 'Access-Control-Allow-Origin' is '*'</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSMethodNotFound\">Reason: Did not find method in CORS header 'Access-Control-Allow-Methods'</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSMIssingAllowCredentials\">Reason: expected 'true' in CORS header 'Access-Control-Allow-Credentials'</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSInvalidAllowHeader\">Reason: invalid token 'xyz' in CORS header 'Access-Control-Allow-Headers'</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSInvalidAllowMethod\">Reason: invalid token 'xyz' in CORS header 'Access-Control-Allow-Methods'</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSMissingAllowHeaderFromPreflight\">Reason: missing token 'xyz' in CORS header 'Access-Control-Allow-Headers' from CORS preflight channel</a></li><li><a href=\"/en-US/docs/Web/HTTP/CORS/Errors/CORSMultipleAllowOriginNotAllowed\">Reason: Multiple CORS header 'Access-Control-Allow-Origin' not allowed</a></li></ol>\n </details>\n </li>\n <li class=\"toggle\">\n <details>\n <summary>Permissions-Policy directives</summary>\n <ol><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/accelerometer\">Permissions-Policy: accelerometer</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/ambient-light-sensor\">Permissions-Policy: ambient-light-sensor</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/attribution-reporting\">Permissions-Policy: attribution-reporting</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/autoplay\">Permissions-Policy: autoplay</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/bluetooth\">Permissions-Policy: bluetooth</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/browsing-topics\">Permissions-Policy: browsing-topics</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/camera\">Permissions-Policy: camera</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/compute-pressure\">Permissions-Policy: compute-pressure</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/display-capture\">Permissions-Policy: display-capture</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/document-domain\">Permissions-Policy: document-domain</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/encrypted-media\">Permissions-Policy: encrypted-media</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/fullscreen\">Permissions-Policy: fullscreen</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/gamepad\">Permissions-Policy: gamepad</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/geolocation\">Permissions-Policy: geolocation</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/gyroscope\">Permissions-Policy: gyroscope</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/hid\">Permissions-Policy: hid</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/identity-credentials-get\">Permissions-Policy: identity-credentials-get</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/idle-detection\">Permissions-Policy: idle-detection</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/local-fonts\">Permissions-Policy: local-fonts</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/magnetometer\">Permissions-Policy: magnetometer</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/microphone\">Permissions-Policy: microphone</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/midi\">Permissions-Policy: midi</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/otp-credentials\">Permissions-Policy: otp-credentials</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/payment\">Permissions-Policy: payment</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/picture-in-picture\">Permissions-Policy: picture-in-picture</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/publickey-credentials-create\">Permissions-Policy: publickey-credentials-create</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/publickey-credentials-get\">Permissions-Policy: publickey-credentials-get</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/screen-wake-lock\">Permissions-Policy: screen-wake-lock</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/serial\">Permissions-Policy: serial</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/speaker-selection\">Permissions-Policy: speaker-selection</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/storage-access\">Permissions-Policy: storage-access</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/usb\">Permissions-Policy: usb</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/web-share\">Permissions-Policy: web-share</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/window-management\">Permissions-Policy: window-management</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTTP/Headers/Permissions-Policy/xr-spatial-tracking\">Permissions-Policy: xr-spatial-tracking</a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li></ol>\n </details>\n </li>\n <li><a href=\"/en-US/docs/Web/HTTP/Resources_and_specifications\">HTTP resources and specifications</a></li>\n </ol>\n","sidebarMacro":"HTTPSidebar","body":[{"type":"prose","value":{"id":null,"title":null,"isH3":false,"content":"<p>\n <strong><em>Hypertext Transfer Protocol (HTTP)</em></strong> is an <a href=\"https://en.wikipedia.org/wiki/Application_Layer\" class=\"external\" target=\"_blank\">application-layer</a> protocol for transmitting hypermedia documents, such as HTML.\n It was designed for communication between web browsers and web servers, but it can also be used for other purposes, such as machine-to-machine communication, programmatic access to APIs, and more.\n</p>\n<p>\n HTTP follows a classical <a href=\"https://en.wikipedia.org/wiki/Client%E2%80%93server_model\" class=\"external\" target=\"_blank\">client-server model</a>, with a client opening a connection to make a request, then waiting until it receives a response from the server.\n HTTP is a <a href=\"https://en.wikipedia.org/wiki/Stateless_protocol\" class=\"external\" target=\"_blank\">stateless protocol</a>, meaning that the server does not keep any session data between two requests, although the later addition of <a href=\"/en-US/docs/Web/HTTP/Cookies\">cookies</a> adds state to some client-server interactions.\n</p>"}},{"type":"prose","value":{"id":"references","title":"References","isH3":false,"content":"<p>The HTTP reference documentation contains detailed information about headers, request methods, status responses, and lists relevant specifications and standards documents.</p>\n<dl>\n <dt id=\"http_headers\"><a href=\"/en-US/docs/Web/HTTP/Headers\">HTTP headers</a></dt>\n <dd>\n <p>Message headers are used to send metadata about a resource or a HTTP message, and to describe the behavior of the client or the server.</p>\n </dd>\n <dt id=\"http_request_methods\"><a href=\"/en-US/docs/Web/HTTP/Methods\">HTTP request methods</a></dt>\n <dd>\n <p>\n Request methods indicate the purpose of the request and what is expected if the request is successful.\n The most common methods are <a href=\"/en-US/docs/Web/HTTP/Methods/GET\"><code>GET</code></a> and <a href=\"/en-US/docs/Web/HTTP/Methods/POST\"><code>POST</code></a> for retrieving and sending data to servers, respectively, but there are other methods which serve different purposes.\n </p>\n </dd>\n <dt id=\"http_response_status_codes\"><a href=\"/en-US/docs/Web/HTTP/Status\">HTTP response status codes</a></dt>\n <dd>\n <p>\n Response status codes indicate the outcome of a specific HTTP request.\n Responses are grouped in five classes: informational, successful, redirections, client errors, and server errors.\n </p>\n </dd>\n <dt id=\"http_resources_and_specifications\"><a href=\"/en-US/docs/Web/HTTP/Resources_and_specifications\">HTTP resources and specifications</a></dt>\n <dd>\n <p>This page lists relevant resources about HTTP since it was first specified in the early 1990s.</p>\n </dd>\n</dl>"}},{"type":"prose","value":{"id":"http_guides","title":"HTTP guides","isH3":false,"content":"<p>\n HTTP is an extensible protocol that relies on concepts like resources and Uniform Resource Identifiers (URIs), a simple message structure, and client-server communication model.\n On top of these concepts, numerous extensions have been developed over the years that add functionality and updated semantics, including additional HTTP methods and headers.\n</p>\n<p>\n The guides below are listed in order from general overviews to specialized, use-case-driven topics.\n Beginners are encouraged to start with the foundational guides before exploring more focused articles.\n</p>\n<dl>\n <dt id=\"overview_of_http\"><a href=\"/en-US/docs/Web/HTTP/Overview\">Overview of HTTP</a></dt>\n <dd>\n <p>The basic features of HTTP, what it can do, its intended use in web architecture, and its position in the protocol stack.</p>\n </dd>\n <dt id=\"a_typical_http_session\"><a href=\"/en-US/docs/Web/HTTP/Session\">A typical HTTP session</a></dt>\n <dd>\n <p>Describes the flow of an HTTP session, from establishing a connection, sending a request, to receiving a response.</p>\n </dd>\n <dt id=\"http_messages\"><a href=\"/en-US/docs/Web/HTTP/Messages\">HTTP messages</a></dt>\n <dd>\n <p>\n HTTP messages transmitted as requests and responses have a defined structure.\n This article describes this general structure, its purpose, and the different types of messages.\n </p>\n </dd>\n <dt id=\"uris\"><a href=\"/en-US/docs/Web/URI\">URIs</a></dt>\n <dd>\n <p>Uniform Resource Identifiers (URIs) are used to describe and locate resources on the web and are an essential component in HTTP requests.</p>\n </dd>\n <dt id=\"mime_types\"><a href=\"/en-US/docs/Web/HTTP/MIME_types\">MIME types</a></dt>\n <dd>\n <p>\n Since HTTP/1.0, different types of content can be transmitted.\n This article explains how this is accomplished using the <a href=\"/en-US/docs/Web/HTTP/Headers/Content-Type\"><code>Content-Type</code></a> header and the MIME standard.\n A shortlist of common types used by web developers can be found in <a href=\"/en-US/docs/Web/HTTP/MIME_types/Common_types\">Common MIME types</a>.\n </p>\n </dd>\n <dt id=\"compression_in_http\"><a href=\"/en-US/docs/Web/HTTP/Compression\">Compression in HTTP</a></dt>\n <dd>\n <p>Browsers and servers compress their messages before sending them over the network to reduce the amount of data that needs to be transmitted, improving transfer speed and bandwidth utilization.</p>\n </dd>\n <dt id=\"http_caching\"><a href=\"/en-US/docs/Web/HTTP/Caching\">HTTP caching</a></dt>\n <dd>\n <p>\n Caching is a highly important mechanism for delivering fast experiences on the Web and for efficient use of resources.\n This article describes different methods of caching and how to use HTTP headers to control them.\n </p>\n </dd>\n <dt id=\"http_authentication\"><a href=\"/en-US/docs/Web/HTTP/Authentication\">HTTP authentication</a></dt>\n <dd>\n <p>\n Authentication is a way to verify the identity of a client when making requests to a server.\n It ensures that only authorized users or systems can access certain resources.\n </p>\n </dd>\n <dt id=\"using_http_cookies\"><a href=\"/en-US/docs/Web/HTTP/Cookies\">Using HTTP cookies</a></dt>\n <dd>\n <p>\n Although HTTP is a stateless protocol, a server can send a <a href=\"/en-US/docs/Web/HTTP/Headers/Set-Cookie\"><code>Set-Cookie</code></a> header with the response.\n The client then returns the cookie's value with every subsequent request to the server in the form of a <a href=\"/en-US/docs/Web/HTTP/Headers/Cookie\"><code>Cookie</code></a> request header.\n This adds the ability to store and exchange a small amount of data which effectively adds state to some client-server interactions.\n </p>\n </dd>\n <dt id=\"redirections_in_http\"><a href=\"/en-US/docs/Web/HTTP/Redirections\">Redirections in HTTP</a></dt>\n <dd>\n <p>\n URL redirection, also known as URL forwarding, is a technique to give more than one URL address to a page, a form, a whole website, or a web application.\n HTTP has a special kind of response, called a HTTP redirect, for this operation.\n </p>\n </dd>\n <dt id=\"http_conditional_requests\"><a href=\"/en-US/docs/Web/HTTP/Conditional_requests\">HTTP conditional requests</a></dt>\n <dd>\n <p>\n In conditional requests, the outcome of a request depends on the value of a validator in the request.\n This method is used heavily in <a href=\"/en-US/docs/Web/HTTP/Caching\">caching</a> and use cases such as resuming a download, preventing lost updates when modifying a document on the server, and more.\n </p>\n </dd>\n <dt id=\"http_range_requests\"><a href=\"/en-US/docs/Web/HTTP/Range_requests\">HTTP range requests</a></dt>\n <dd>\n <p>\n A range request asks the server to send a specific part (or parts) of a resource back to a client instead of the full resource.\n Range requests are useful for cases when a client knows they need only part of a large file, or for cases where an application allows the user to pause and resume a download.\n </p>\n </dd>\n <dt id=\"content_negotiation\"><a href=\"/en-US/docs/Web/HTTP/Content_negotiation\">Content negotiation</a></dt>\n <dd>\n <p>\n HTTP defines a set of message headers, starting with <a href=\"/en-US/docs/Web/HTTP/Headers/Accept\"><code>Accept</code></a> as a way for a browser to announce the format, language, or encoding it prefers.\n This article explains how this advertisement happens, how the server is expected to react, and how it chooses the most adequate response to a request.\n </p>\n </dd>\n <dt id=\"connection_management_in_http1.x\"><a href=\"/en-US/docs/Web/HTTP/Connection_management_in_HTTP_1.x\">Connection management in HTTP/1.x</a></dt>\n <dd>\n <p>\n HTTP/1.1 was the first version of HTTP to support persistent connections and pipelining.\n This article explains both concepts, including the pros and cons of each.\n </p>\n </dd>\n <dt id=\"evolution_of_http\"><a href=\"/en-US/docs/Web/HTTP/Evolution_of_HTTP\">Evolution of HTTP</a></dt>\n <dd>\n <p>\n HTTP was created in the early 1990s and has been extended several times.\n This article goes through its history and describes HTTP/0.9, HTTP/1.0, HTTP/1.1, through HTTP/2 and HTTP/3, as well as novelties introduced over the years.\n </p>\n </dd>\n <dt id=\"protocol_upgrade_mechanism\"><a href=\"/en-US/docs/Web/HTTP/Protocol_upgrade_mechanism\">Protocol upgrade mechanism</a></dt>\n <dd>\n <p>\n HTTP/1.1 provides a mechanism to upgrade an already-established connection to a different protocol using the <a href=\"/en-US/docs/Web/HTTP/Headers/Upgrade\"><code>Upgrade</code></a> header.\n A client can upgrade a connection from HTTP/1.1 to HTTP/2, or an HTTP(S) connection to a <a href=\"/en-US/docs/Web/API/WebSocket\">WebSocket</a> (<code>ws</code> / <code>wss</code>).\n </p>\n </dd>\n <dt id=\"proxy_servers_and_tunneling\"><a href=\"/en-US/docs/Web/HTTP/Proxy_servers_and_tunneling\">Proxy servers and tunneling</a></dt>\n <dd>\n <p>\n A proxy can be on the user's local computer, or anywhere between the user's computer and a destination server on the Internet.\n This page outlines some basics about proxies and introduces a few configuration options.\n </p>\n </dd>\n <dt id=\"http_client_hints\"><a href=\"/en-US/docs/Web/HTTP/Client_hints\">HTTP Client hints</a></dt>\n <dd>\n <p>\n Client Hints are a set of response headers that a server can use to proactively request information from a client about the device, network, user, and user-agent-specific preferences.\n The server can then determine which resources to send, based on the information that the client chooses to provide.\n </p>\n </dd>\n <dt id=\"network_error_logging\"><a href=\"/en-US/docs/Web/HTTP/Network_Error_Logging\">Network Error Logging</a> <abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></dt>\n <dd>\n <p>\n Network Error Logging is a mechanism that can be configured via the <code>NEL</code> HTTP response header.\n This experimental header allows websites and applications to opt-in to receive reports about failed (or even successful) network fetches from supporting browsers.\n </p>\n </dd>\n <dt id=\"browser_detection_using_the_user_agent\"><a href=\"/en-US/docs/Web/HTTP/Browser_detection_using_the_user_agent\">Browser detection using the user agent</a></dt>\n <dd>\n <p>\n It's very rarely a good idea to use user agent sniffing to detect a browser, but there are edge cases that require it.\n This document will guide you in doing this as correctly as possible when this is necessary, with an emphasis on considerations to make before embarking on this route.\n </p>\n </dd>\n <dt id=\"configuring_servers_for_ogg_media\"><a href=\"/en-US/docs/Web/HTTP/Configuring_servers_for_Ogg_media\">Configuring servers for Ogg media</a></dt>\n <dd>\n <p>\n This guide covers a few server configuration changes that may be necessary for your web server to correctly serve Ogg media files.\n This information may also be useful if you encounter other media types your server isn't already configured to recognize.\n </p>\n </dd>\n</dl>"}},{"type":"prose","value":{"id":"security_and_privacy","title":"Security and privacy","isH3":true,"content":"<dl>\n <dt id=\"mozilla_web_security_guidelines\"><a href=\"https://infosec.mozilla.org/guidelines/web_security\" class=\"external\" target=\"_blank\">Mozilla web security guidelines</a></dt>\n <dd>\n <p>A collection of tips to help operational teams with creating secure web applications.</p>\n </dd>\n <dt id=\"permissions_policy\"><a href=\"/en-US/docs/Web/HTTP/Permissions_Policy\">Permissions Policy</a></dt>\n <dd>\n <p>\n Permissions Policy provides mechanisms for web developers to explicitly declare what functionality can and cannot be used on a website.\n You define a set of \"policies\" that restrict what APIs the site's code can access or modify the browser's default behavior for certain features.\n </p>\n </dd>\n <dt id=\"cross-origin_resource_sharing_cors\"><a href=\"/en-US/docs/Web/HTTP/CORS\">Cross-Origin Resource Sharing (CORS)</a></dt>\n <dd>\n <p>\n Cross-site HTTP requests are requests for resources from a different domain than that of the resource making the request.\n Web pages today very commonly load cross-site resources, for example, a page 'Domain A' (<code>http://domaina.example/</code>) requests an image on 'Domain B' (<code>http://domainb.foo/image.jpg</code>) via the <code>img</code> element.\n CORS allows web developers to control how their site reacts to cross-site requests.\n </p>\n </dd>\n <dt id=\"content_security_policy_csp\"><a href=\"/en-US/docs/Web/HTTP/CSP\">Content Security Policy (CSP)</a></dt>\n <dd>\n <p>\n CSP allows website administrators to use the <a href=\"/en-US/docs/Web/HTTP/Headers/Content-Security-Policy\"><code>Content-Security-Policy</code></a> response header to control which resources the client is allowed to load for a given page.\n The CSP guide describes the overall Content Security Policy mechanism which helps detect and mitigate certain types of attacks, including Cross-Site Scripting (XSS) and data injection attacks.\n </p>\n </dd>\n <dt id=\"cross-origin_resource_policy_corp\"><a href=\"/en-US/docs/Web/HTTP/Cross-Origin_Resource_Policy\">Cross-Origin Resource Policy (CORP)</a></dt>\n <dd>\n <p>CORP lets websites and applications opt in to protection against specific requests from other origins (such as those issued with elements like <code><script></code> and <code><img></code>), to mitigate speculative side-channel attacks.</p>\n </dd>\n</dl>"}},{"type":"prose","value":{"id":"tools_resources","title":"Tools & resources","isH3":false,"content":"<p>Helpful tools and resources for understanding and debugging HTTP.</p>\n<dl>\n <dt id=\"firefox_developer_tools\"><a href=\"https://firefox-source-docs.mozilla.org/devtools-user/index.html\" class=\"external\" target=\"_blank\">Firefox Developer Tools</a></dt>\n <dd>\n <p><a href=\"https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/index.html\" class=\"external\" target=\"_blank\">Network monitor</a></p>\n </dd>\n <dt id=\"http_observatory\"><a href=\"/en-US/observatory\">HTTP Observatory</a></dt>\n <dd>\n <p>A project designed to help developers, system administrators, and security professionals configure their sites safely and securely.</p>\n </dd>\n <dt id=\"redbot\"><a href=\"https://redbot.org/\" class=\"external\" target=\"_blank\">RedBot</a></dt>\n <dd>\n <p>Tools to check your cache-related headers.</p>\n </dd>\n <dt id=\"nghttp2\"><a href=\"https://github.com/nghttp2/nghttp2\" class=\"external\" target=\"_blank\">nghttp2</a></dt>\n <dd>\n <p>An HTTP/2 client, server and proxy implementation written in C with load test and benchmarking tools and an HPACK encoder and decoder.</p>\n </dd>\n <dt id=\"curl\"><a href=\"https://github.com/curl/curl\" class=\"external\" target=\"_blank\">curl</a></dt>\n <dd>\n <p>\n A command-line tool for transferring data specified with URL syntax.\n Supports HTTP, HTTPS, WS, WSS, among many other protocols.\n </p>\n </dd>\n <dt id=\"how_browsers_work_2011\"><a href=\"https://web.dev/articles/howbrowserswork\" class=\"external\" target=\"_blank\">How Browsers Work (2011)</a></dt>\n <dd>\n <p>A very comprehensive article on browser internals and request flow through HTTP protocol.</p>\n </dd>\n</dl>"}}],"toc":[{"text":"References","id":"references"},{"text":"HTTP guides","id":"http_guides"},{"text":"Tools & resources","id":"tools_resources"}],"summary":"Hypertext Transfer Protocol (HTTP) is an application-layer protocol for transmitting hypermedia documents, such as HTML.\n It was designed for communication between web browsers and web servers, but it can also be used for other purposes, such as machine-to-machine communication, programmatic access to APIs, and more.","popularity":0.1018,"modified":"2024-10-02T17:31:02.000Z","other_translations":[{"locale":"de","title":"HTTP","native":"Deutsch"},{"locale":"es","title":"HTTP","native":"Español"},{"locale":"fr","title":"HTTP","native":"Français"},{"locale":"ja","title":"HTTP","native":"日本語"},{"locale":"ko","title":"HTTP","native":"한국어"},{"locale":"pt-BR","title":"HTTP","native":"Português (do Brasil)"},{"locale":"ru","title":"HTTP","native":"Русский"},{"locale":"zh-CN","title":"HTTP","native":"中文 (简体)"},{"locale":"zh-TW","title":"HTTP","native":"正體中文 (繁體)"}],"pageType":"landing-page","source":{"folder":"en-us/web/http","github_url":"https://github.com/mdn/content/blob/main/files/en-us/web/http/index.md","last_commit_url":"https://github.com/mdn/content/commit/1c0dda60cb2b680a753264b538e2c46776ecd837","filename":"index.md"},"short_title":"HTTP","parents":[{"uri":"/en-US/docs/Web","title":"References"},{"uri":"/en-US/docs/Web/HTTP","title":"HTTP"}],"pageTitle":"HTTP | MDN","noIndexing":false}}</script></body></html>