Time to Stable

For a given set of browsers, what APIs are in all of them and how many days it take for the API to land in the first browser to the last.

Example Comparisons
Browsers
Features

Summary

A count of the number of APIs that landed in A first and B last.
Last in ChromeLast in Safari
First in Chrome 98
First in Safari 79

Average time for an API to become available across Chrome and Safari

177 APIs took an average of 1173.04 days to become available to use.

API breakdown:

Average time to landing by year of first landing

If a feature landed in the earliest browser in 20XX it took Y days on average to become available in the last browser (when considering Chrome and Safari). TTA (time to available).
HTTP APIsHTTP TTA
2003 581998.00
2008 91151.00
2009 10231.00
2010 2689.50
2011 5225.00
2012 1573.00
2013 15244.60
2014 11283.00
2015 9690.89
2016 121092.67
2017 171163.76
2018 71142.14
2019 91007.33
2020 61095.67
2021 1497.00
2022 6391.00
2023 4752.75
2024 4554.00
2025 1227.00

The Tortoise and the Hare

There is a natural tension on the web with respect to browser engines. Every engine has their own set of priorities which define the level of investment that they choose to make and on which areas they choose to make it.

A developer naturally wants their experiences to be available to the widest audience possible and these differing priorities create an unevenness on the platform (a lumpiness) making it harder for developers to build experiences that work everywhere.

This section highlights where browsers are pushing and pulling on the platform.

Sprinters

This table is designed to show which browsers are pushing on the platform the most.

Adding features to quickly is not always desired because developers are unlikely to adopt those features in their sites or apps.

For a given year, if a feature landed in Browser X first, how many days it take on average to be available in Chrome and Safari. TTA (time to available).
Year HTTPHTTP TTA
2003
  Safari 581998.00
2008
  Safari 4678.00
  Chrome 51529.40
2009
  Safari 10231.00
2010
  Chrome 2689.50
2011
  Chrome 5225.00
2012
  Chrome 1573.00
2013
  Chrome 14243.00
  Safari 1267.00
2014
  Chrome 11283.00
2015
  Chrome 9690.89
2016
  Chrome 91140.78
  Safari 3948.33
2017
  Chrome 161228.63
  Safari 1126.00
2018
  Chrome 61303.17
  Safari 1176.00
2019
  Chrome 81117.38
  Safari 1127.00
2020
  Chrome 61095.67
2021
  Chrome 1497.00
2022
  Chrome 6391.00
2023
  Chrome 4752.75
2024
  Chrome 4554.00
2025
  Chrome 1227.00

Plodders

This table is designed to show which browsers are pulling on the platform the most.

For a feature that first landed in year X, how many days did it take on average for the last browser to catch up across Chrome and Safari. TTA (time to available).
Year HTTP countHTTP TTA
2003
  Chrome 581998.00
2008
  Chrome 4678.00
  Safari 51529.40
2009
  Chrome 10231.00
2010
  Safari 2689.50
2011
  Safari 5225.00
2012
  Safari 1573.00
2013
  Safari 14243.00
  Chrome 1267.00
2014
  Safari 11283.00
2015
  Safari 9690.89
2016
  Safari 91140.78
  Chrome 3948.33
2017
  Safari 161228.63
  Chrome 1126.00
2018
  Safari 61303.17
  Chrome 1176.00
2019
  Safari 81117.38
  Chrome 1127.00
2020
  Safari 61095.67
2021
  Safari 1497.00
2022
  Safari 6391.00
2023
  Safari 4752.75
2024
  Safari 4554.00
2025
  Safari 1227.00

Stable APIs

Below is a list of features that are in Chrome and Safari

Raw Data

Quick Links:

HTTP Data

API First Browser Date Last Browser Date Days Notes
http.data-url 📋Safari3/18/2008 Chrome1/25/2010678
Edge: Before Edge 79, the maximum size supported is 4GB.Internet Explorer: Since Internet Explorer 9, the maximum size supported is 4GB.Internet Explorer: In Internet Explorer 8, the maximum size supported is 32kB.
http.data-url.css_files Safari3/18/2008 Chrome1/25/2010678
http.data-url.html_files Safari3/18/2008 Chrome1/25/2010678
http.data-url.js_files Safari3/18/2008 Chrome1/25/2010678
http.data-url.top_level_navigation_blocked Chrome7/25/2017 Safari9/16/20201149
http.headers.Accept 📋Safari6/23/2003 Chrome12/11/20081998
Firefox: In Firefox 66, the default Accept header value changed to */*.Firefox for Android: In Firefox for Android 66, the default Accept header value changed to */*.
http.headers.Accept-Encoding 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Accept-Encoding.br 📋Chrome4/13/2016 Safari9/19/2017524
Safari: Unsupported before macOS 10.13 High Sierra.
http.headers.Accept-Encoding.zstd 📋Chrome3/19/2024 Safari2/11/2026694
Safari: Before macOS 26.3 Tahoe, this header value is not sent.
http.headers.Accept-Language 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Accept-Ranges 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Access-Control-Allow-Credentials 📋Safari6/8/2009 Chrome1/25/2010231
http.headers.Access-Control-Allow-Headers 📋Safari6/8/2009 Chrome1/25/2010231
http.headers.Access-Control-Allow-Headers.wildcard Chrome12/6/2017 Safari9/19/2019652
http.headers.Access-Control-Allow-Methods 📋Safari6/8/2009 Chrome1/25/2010231
http.headers.Access-Control-Allow-Methods.wildcard Chrome12/6/2017 Safari9/19/2019652
http.headers.Access-Control-Allow-Origin 📋Safari6/8/2009 Chrome1/25/2010231
http.headers.Access-Control-Expose-Headers 📋Safari6/8/2009 Chrome1/25/2010231
http.headers.Access-Control-Expose-Headers.wildcard Chrome3/6/2018 Safari9/19/2019562
http.headers.Access-Control-Max-Age 📋Safari6/8/2009 Chrome1/25/2010231
http.headers.Access-Control-Request-Headers 📋Safari6/8/2009 Chrome1/25/2010231
http.headers.Access-Control-Request-Method 📋Safari6/8/2009 Chrome1/25/2010231
http.headers.Age 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Alt-Svc 📋Chrome7/20/2016 Safari9/18/20232616
Firefox: Only supports draft-04Firefox for Android: Only supports draft-04
http.headers.Authorization 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Authorization.Basic 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Authorization.Digest 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Authorization.Digest.md5 Safari6/23/2003 Chrome12/11/20081998
http.headers.Authorization.NTLM Chrome12/11/2008 Safari10/22/20131776
http.headers.Authorization.Negotiate 📋Chrome12/11/2008 Safari10/22/20131776
http.headers.Cache-Control 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Cache-Control.stale-while-revalidate 📋Chrome6/4/2019 Safari9/16/2020470
http.headers.Clear-Site-Data 📋Chrome9/5/2017 Safari9/18/20232204
http.headers.Clear-Site-Data.cache 📋Chrome3/6/2018 Safari9/18/20232022
Chrome: Setting this value may increase response duration (see bug 40233601.Chrome: Setting this value may prevent a page from fully load (see bug 41343050.Chrome Android: Setting this value may increase response duration (see bug 40233601.Chrome Android: Setting this value may prevent a page from fully load (see bug 41343050.Edge: Setting this value may increase response duration (see bug 40233601.Quest Browser: Setting this value may increase response duration (see bug 40233601.Opera: Setting this value may increase response duration (see bug 40233601.Opera: Setting this value may prevent a page from fully load (see bug 41343050.Opera Android: Setting this value may increase response duration (see bug 40233601.Opera Android: Setting this value may prevent a page from fully load (see bug 41343050.Samsung Internet: Setting this value may increase response duration (see bug 40233601.WebView Android: Setting this value may increase response duration (see bug 40233601.WebView Android: Setting this value may prevent a page from fully load (see bug 41343050.
http.headers.Clear-Site-Data.cookies 📋Chrome9/5/2017 Safari9/18/20232204
http.headers.Clear-Site-Data.secure_context_required Chrome9/5/2017 Safari9/18/20232204
http.headers.Clear-Site-Data.storage 📋Chrome9/5/2017 Safari9/18/20232204
http.headers.Clear-Site-Data.wildcard 📋Chrome9/12/2023 Safari9/18/20236
http.headers.Connection 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Content-Disposition 📋Safari6/23/2003 Chrome12/11/20081998
Chrome: When saving documents, the document title is used instead of the filename parameter if the disposition type is inline. See bug 352093465.Chrome Android: When saving documents, the document title is used instead of the filename parameter if the disposition type is inline. See bug 352093465.Firefox: From version 82, if an <a> element's download attribute is set (for a same-origin URL) then the inline directive is ignored. Earlier versions did not match the specification and respected the header directive over the attribute. See bug 1658877.Firefox for Android: From version 82, if an <a> element's download attribute is set (for a same-origin URL) then the inline directive is ignored. Earlier versions did not match the specification and respected the header directive over the attribute. See bug 1658877.Quest Browser: When saving documents, the document title is used instead of the filename parameter if the disposition type is inline. See bug 352093465.Opera: When saving documents, the document title is used instead of the filename parameter if the disposition type is inline. See bug 352093465.Opera Android: When saving documents, the document title is used instead of the filename parameter if the disposition type is inline. See bug 352093465.Safari: When saving documents, the document title is used instead of the filename parameter if the disposition type is inline. See bug 18384.Safari on iOS: When saving documents, the document title is used instead of the filename parameter if the disposition type is inline. See bug 18384.Samsung Internet: When saving documents, the document title is used instead of the filename parameter if the disposition type is inline. See bug 352093465.WebView Android: When saving documents, the document title is used instead of the filename parameter if the disposition type is inline. See bug 352093465.WebView on iOS: When saving documents, the document title is used instead of the filename parameter if the disposition type is inline. See bug 18384.
http.headers.Content-Encoding 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Content-Encoding.br 📋Chrome4/13/2016 Safari9/19/2017524
Safari: Unsupported before macOS 10.13 High Sierra.
http.headers.Content-Encoding.zstd 📋Chrome3/19/2024 Safari2/11/2026694
Safari: Before macOS 26.3 Tahoe, Safari cannot decode Zstandard responses.
http.headers.Content-Language 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Content-Length 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Content-Length.cors_response_safelist Safari3/25/2019 Chrome7/30/2019127
http.headers.Content-Location 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Content-Range 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Content-Security-Policy 📋Chrome2/21/2013 Safari10/22/2013243
Internet Explorer: Only supporting 'sandbox' directive.
http.headers.Content-Security-Policy.base-uri 📋Chrome1/21/2015 Safari9/20/2016608
http.headers.Content-Security-Policy.block-all-mixed-content Chrome7/21/2015 Safari9/20/2016427
Chrome: Will be removed, see bug 40260100.Chrome Android: Will be removed, see bug 40260100.Edge: Will be removed, see bug 40260100.Quest Browser: Will be removed, see bug 40260100.Opera: Will be removed, see bug 40260100.Opera Android: Will be removed, see bug 40260100.Samsung Internet: Will be removed, see bug 40260100.WebView Android: Will be removed, see bug 40260100.
http.headers.Content-Security-Policy.child-src 📋Chrome1/21/2015 Safari9/20/2016608
http.headers.Content-Security-Policy.connect-src 📋Chrome2/21/2013 Safari10/22/2013243
Firefox: Before Firefox 50, ping attributes of <a> elements weren't covered by connect-src.
http.headers.Content-Security-Policy.default-src 📋Chrome2/21/2013 Safari10/22/2013243
http.headers.Content-Security-Policy.font-src 📋Chrome2/21/2013 Safari10/22/2013243
http.headers.Content-Security-Policy.form-action 📋Chrome1/21/2015 Safari9/20/2016608
http.headers.Content-Security-Policy.form-action.blocks_redirects Chrome12/6/2017 Safari4/12/2018127
http.headers.Content-Security-Policy.frame-ancestors 📋Chrome1/21/2015 Safari9/20/2016608
Firefox: Before Firefox 58, frame-ancestors is ignored in Content-Security-Policy-Report-Only.Firefox for Android: Before Firefox for Android 58, frame-ancestors is ignored in Content-Security-Policy-Report-Only.
http.headers.Content-Security-Policy.frame-src 📋Chrome2/21/2013 Safari10/22/2013243
http.headers.Content-Security-Policy.img-src 📋Chrome2/21/2013 Safari10/22/2013243
http.headers.Content-Security-Policy.manifest-src 📋Chrome1/21/2015 Safari9/19/2017972
http.headers.Content-Security-Policy.media-src 📋Chrome2/21/2013 Safari10/22/2013243
http.headers.Content-Security-Policy.meta-element-support Chrome2/21/2013 Safari10/22/2013243
http.headers.Content-Security-Policy.object-src 📋Chrome2/21/2013 Safari10/22/2013243
http.headers.Content-Security-Policy.report-sample Chrome6/5/2017 Safari3/14/20221743
http.headers.Content-Security-Policy.report-to 📋Chrome10/16/2018 Safari3/27/20231623
http.headers.Content-Security-Policy.report-uri 📋Chrome2/21/2013 Safari10/22/2013243
http.headers.Content-Security-Policy.require-trusted-types-for 📋Chrome5/19/2020 Safari9/15/20251945
http.headers.Content-Security-Policy.sandbox 📋Chrome2/21/2013 Safari10/22/2013243
http.headers.Content-Security-Policy.script-src 📋Chrome2/21/2013 Safari10/22/2013243
http.headers.Content-Security-Policy.script-src.external_scripts 📋Chrome6/5/2017 Safari7/20/20221871
http.headers.Content-Security-Policy.script-src.inline-speculation-rules Chrome2/7/2023 Safari12/12/20251039
http.headers.Content-Security-Policy.script-src.wasm-unsafe-eval Chrome1/4/2022 Safari9/12/2022251
http.headers.Content-Security-Policy.script-src-attr 📋Chrome6/4/2019 Safari3/14/20221014
http.headers.Content-Security-Policy.script-src-elem 📋Chrome6/4/2019 Safari3/14/20221014
http.headers.Content-Security-Policy.strict-dynamic Chrome7/20/2016 Safari3/14/20222063
http.headers.Content-Security-Policy.style-src 📋Chrome2/21/2013 Safari10/22/2013243
http.headers.Content-Security-Policy.style-src-attr 📋Chrome6/4/2019 Safari3/14/20221014
http.headers.Content-Security-Policy.style-src-elem 📋Chrome6/4/2019 Safari12/12/20252383
Safari: The style-src-elem directive was parsed, but had no effect. See bug 276931.Safari on iOS: The style-src-elem directive was parsed, but had no effect. See bug 276931.WebView on iOS: The style-src-elem directive was parsed, but had no effect. See bug 276931.
http.headers.Content-Security-Policy.trusted-types 📋Chrome5/19/2020 Safari9/15/20251945
http.headers.Content-Security-Policy.unsafe-hashes Chrome9/4/2018 Safari3/14/20221287
http.headers.Content-Security-Policy.upgrade-insecure-requests 📋Chrome5/19/2015 Safari3/27/2017678
http.headers.Content-Security-Policy.worker-src 📋Chrome6/5/2017 Safari5/16/20221806
Chrome: Chrome 59 and higher skips the deprecated child-src directive.Chrome Android: Chrome Android 59 and higher skips the deprecated child-src directive.Quest Browser: Quest Browser 5.0 and higher skips the deprecated child-src directive.Opera: Opera 46 and higher skips the deprecated child-src directive.Opera Android: Opera Android 43 and higher skips the deprecated child-src directive.WebView Android: WebView Android 59 and higher skips the deprecated child-src directive.
http.headers.Content-Security-Policy.worker_support Safari9/20/2016 Chrome1/25/2017127
http.headers.Content-Security-Policy-Report-Only 📋Chrome2/21/2013 Safari10/22/2013243
http.headers.Content-Type 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Cookie 📋Safari6/23/2003 Chrome12/11/20081998
Safari: Cookies with Secure flag are not sent to unsecured http://localhost/ endpoints. See bug 281149.Safari on iOS: Cookies with Secure flag are not sent to unsecured http://localhost/ endpoints. See bug 281149.WebView on iOS: Cookies with Secure flag are not sent to unsecured http://localhost/ endpoints. See bug 281149.
http.headers.Cross-Origin-Embedder-Policy 📋Chrome5/19/2020 Safari12/13/2021573
http.headers.Cross-Origin-Opener-Policy 📋Chrome5/19/2020 Safari12/13/2021573
http.headers.Cross-Origin-Opener-Policy.noopener-allow-popups 📋Chrome11/12/2024 Safari3/31/2025139
http.headers.Cross-Origin-Resource-Policy 📋Safari9/17/2018 Chrome3/12/2019176
Chrome: Until version 75, downloads for files with this header would fail in Chrome. See bug 41452948.Chrome: From version 80 to 85, linearized PDFs served inline with this header fail to render properly. See bug 40127935. From version 86, partial PDF loading is disabled.Chrome Android: Until version 75, downloads for files with this header would fail in Chrome Android. See bug 41452948.Chrome Android: From version 80 to 85, linearized PDFs served inline with this header fail to render properly. See bug 40127935. From version 86, partial PDF loading is disabled.Quest Browser: Until version 7.0, downloads for files with this header would fail in Quest Browser. See bug 41452948.Quest Browser: From version 9.0 to 85, linearized PDFs served inline with this header fail to render properly. See bug 40127935. From version 12.0, partial PDF loading is disabled.Opera: Until version 62, downloads for files with this header would fail in Opera. See bug 41452948.Opera: From version 67 to 85, linearized PDFs served inline with this header fail to render properly. See bug 40127935. From version 72, partial PDF loading is disabled.Opera Android: Until version 54, downloads for files with this header would fail in Opera Android. See bug 41452948.Opera Android: From version 57 to 85, linearized PDFs served inline with this header fail to render properly. See bug 40127935. From version 61, partial PDF loading is disabled.WebView Android: Until version 75, downloads for files with this header would fail in WebView Android. See bug 41452948.WebView Android: From version 80 to 85, linearized PDFs served inline with this header fail to render properly. See bug 40127935. From version 86, partial PDF loading is disabled.
http.headers.Date 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.ETag 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Expires 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.From 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Host 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.If-Match 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.If-Modified-Since 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.If-None-Match 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.If-Range 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.If-Unmodified-Since 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Keep-Alive 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Last-Modified 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Link 📋Chrome6/21/2022 Safari9/18/2023454
http.headers.Link.fetchpriority 📋Chrome6/21/2022 Safari12/11/2023538
http.headers.Location 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Origin 📋Safari6/23/2003 Chrome12/11/20081998
Edge: Not sent with POST requestsFirefox: Not sent with POST requests, see bug 446344.Firefox for Android: Not sent with POST requests, see bug 446344.
http.headers.Pragma 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Proxy-Authenticate 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Range 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Range.cors_safe Chrome3/1/2022 Safari9/12/2022195
http.headers.Referer 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Referer.length_limit_4096B Chrome9/10/2019 Safari9/16/2020372
http.headers.Referrer-Policy 📋Chrome1/25/2017 Safari4/12/2018442
http.headers.Referrer-Policy.default_strict-origin-when-cross-origin Chrome8/25/2020 Safari9/20/2021391
http.headers.Referrer-Policy.same-origin Chrome9/5/2017 Safari4/12/2018219
http.headers.Referrer-Policy.strict-origin Chrome9/5/2017 Safari4/12/2018219
http.headers.Referrer-Policy.strict-origin-when-cross-origin Chrome9/5/2017 Safari4/12/2018219
http.headers.Refresh 📋Safari6/23/2003 Chrome12/11/20081998
Firefox: From version 136 the HTTP Referer header is sent following a refresh that redirects to another page (if permitted)Firefox for Android: From version 136 the HTTP Referer header is sent following a refresh that redirects to another page (if permitted)
http.headers.Reporting-Endpoints 📋Chrome11/15/2021 Safari3/27/2023497
http.headers.Sec-Fetch-Dest 📋Chrome2/4/2020 Safari3/27/20231147
http.headers.Sec-Fetch-Mode 📋Chrome7/30/2019 Safari3/27/20231336
http.headers.Sec-Fetch-Site 📋Chrome7/30/2019 Safari3/27/20231336
http.headers.Sec-Purpose.speculationrules Chrome2/7/2023 Safari12/12/20251039
http.headers.Sec-Speculation-Tags 📋Chrome4/29/2025 Safari12/12/2025227
http.headers.Sec-WebSocket-Accept 📋Chrome12/13/2011 Safari7/25/2012225
http.headers.Sec-WebSocket-Extensions 📋Chrome12/13/2011 Safari7/25/2012225
http.headers.Sec-WebSocket-Key 📋Chrome12/13/2011 Safari7/25/2012225
http.headers.Sec-WebSocket-Protocol 📋Chrome12/13/2011 Safari7/25/2012225
http.headers.Sec-WebSocket-Version 📋Chrome12/13/2011 Safari7/25/2012225
http.headers.Server 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Server-Timing 📋Chrome3/6/2018 Safari3/27/20231847
http.headers.Service-Worker 📋Chrome10/7/2014 Safari4/12/20181283
http.headers.Service-Worker-Allowed 📋Chrome4/14/2015 Safari4/12/20181094
http.headers.Service-Worker-Navigation-Preload 📋Chrome6/5/2017 Safari3/14/20221743
http.headers.Set-Cookie 📋Safari6/23/2003 Chrome12/11/20081998
Safari: Cookies with Secure flag are not sent to unsecured http://localhost/ endpoints. See bug 281149.Safari on iOS: Cookies with Secure flag are not sent to unsecured http://localhost/ endpoints. See bug 281149.WebView on iOS: Cookies with Secure flag are not sent to unsecured http://localhost/ endpoints. See bug 281149.
http.headers.Set-Cookie.HttpOnly Chrome12/11/2008 Safari6/7/2010543
http.headers.Set-Cookie.Max-Age Safari6/23/2003 Chrome12/11/20081998
http.headers.Set-Cookie.Partitioned 📋Chrome5/30/2023 Safari12/12/2025927
http.headers.Set-Cookie.SameSite 📋Chrome5/25/2016 Safari9/19/20191212
Safari: Safari 13 on macOS 10.14 (Mojave), treats SameSite=None and invalid values as Strict. This is fixed in version 10.15 (Catalina) and later.Safari: Treats SameSite=None and invalid values as Strict in macOS before 10.15 Catalina. See bug 198181.Safari on iOS: Treats SameSite=None and invalid values as Strict in iOS before 13. See bug 198181.WebView on iOS: Treats SameSite=None and invalid values as Strict in iOS before 13. See bug 198181.
http.headers.Set-Cookie.SameSite.Lax Chrome5/25/2016 Safari9/17/2018845
http.headers.Set-Cookie.SameSite.None Chrome5/29/2018 Safari9/19/2019478
Chrome: Rejects cookies with SameSite=None. See SameSite=None: Known Incompatible Clients.Chrome Android: Rejects cookies with SameSite=None. See SameSite=None: Known Incompatible Clients.Quest Browser: Rejects cookies with SameSite=None. See SameSite=None: Known Incompatible Clients.Opera: Rejects cookies with SameSite=None. See SameSite=None: Known Incompatible Clients.Opera Android: Rejects cookies with SameSite=None. See SameSite=None: Known Incompatible Clients.Safari: Not supported before macOS version 10.15 (Catalina).Samsung Internet: Rejects cookies with SameSite=None. See SameSite=None: Known Incompatible Clients.WebView Android: Rejects cookies with SameSite=None. See SameSite=None: Known Incompatible Clients.
http.headers.Set-Cookie.SameSite.Strict Chrome5/25/2016 Safari9/17/2018845
http.headers.Set-Cookie.host_secure_prefixes Chrome3/2/2016 Safari9/19/20191296
http.headers.SourceMap 📋Chrome3/28/2012 Safari10/22/2013573
Chrome: Not supported for ECMAScript Modules (<script type="module">). See bug 40854862.Chrome Android: Not supported for ECMAScript Modules (<script type="module">). See bug 40854862.Edge: Not supported for ECMAScript Modules (<script type="module">). See bug 40854862.Quest Browser: Not supported for ECMAScript Modules (<script type="module">). See bug 40854862.Opera: Not supported for ECMAScript Modules (<script type="module">). See bug 40854862.Opera Android: Not supported for ECMAScript Modules (<script type="module">). See bug 40854862.Samsung Internet: Not supported for ECMAScript Modules (<script type="module">). See bug 40854862.WebView Android: Not supported for ECMAScript Modules (<script type="module">). See bug 40854862.
http.headers.Speculation-Rules 📋Chrome1/23/2024 Safari12/12/2025689
http.headers.Strict-Transport-Security 📋Chrome1/25/2010 Safari10/22/20131366
http.headers.TE 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Timing-Allow-Origin 📋Chrome10/12/2016 Safari9/19/2017342
http.headers.Transfer-Encoding 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Upgrade 📋Chrome5/25/2010 Safari6/7/201013
http.headers.Upgrade-Insecure-Requests 📋Chrome7/21/2015 Safari3/27/2017615
http.headers.User-Agent 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Vary 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.Via 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.WWW-Authenticate 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.WWW-Authenticate.Basic 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.WWW-Authenticate.Digest 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.WWW-Authenticate.Digest.md5 Safari6/23/2003 Chrome12/11/20081998
http.headers.WWW-Authenticate.NTLM Chrome12/11/2008 Safari10/22/20131776
http.headers.WWW-Authenticate.Negotiate 📋Chrome12/11/2008 Safari10/22/20131776
http.headers.Warning 📋Safari6/23/2003 Chrome12/11/20081998
http.headers.X-Content-Type-Options 📋Safari9/19/2017 Chrome1/23/2018126
Chrome: Not supported for stylesheets.Chrome Android: Not supported for stylesheets.Opera: Not supported for stylesheets.Opera Android: Not supported for stylesheets.Samsung Internet: Not supported for stylesheets.WebView Android: Not supported for stylesheets.
http.headers.X-Frame-Options 📋Safari6/8/2009 Chrome1/25/2010231
http.headers.X-Frame-Options.SAMEORIGIN Safari6/8/2009 Chrome1/25/2010231
Chrome: Starting in Chrome 61, this applies to all of a frame's ancestors.Chrome Android: Starting in Chrome Android 61, this applies to all of a frame's ancestors.Firefox: Starting in Firefox 59, this applies to all of a frame's ancestors.Firefox for Android: Starting in Firefox for Android 59, this applies to all of a frame's ancestors.Quest Browser: Starting in Quest Browser 5.0, this applies to all of a frame's ancestors.Opera: Starting in Opera 48, this applies to all of a frame's ancestors.Opera Android: Starting in Opera Android 45, this applies to all of a frame's ancestors.Samsung Internet: Starting in Samsung Internet 8.0, this applies to all of a frame's ancestors.WebView Android: Starting in WebView Android 61, this applies to all of a frame's ancestors.
http.methods.CONNECT 📋Safari6/23/2003 Chrome12/11/20081998
http.methods.DELETE 📋Safari6/23/2003 Chrome12/11/20081998
http.methods.GET 📋Safari6/23/2003 Chrome12/11/20081998
http.methods.HEAD 📋Safari6/23/2003 Chrome12/11/20081998
http.methods.OPTIONS 📋Safari6/23/2003 Chrome12/11/20081998
http.methods.POST 📋Safari6/23/2003 Chrome12/11/20081998
http.methods.PUT 📋Safari6/23/2003 Chrome12/11/20081998
http.mixed-content 📋Safari3/21/2016 Chrome12/10/20191359
http.mixed-content.blockable_mixed_content 📋Safari3/21/2016 Chrome12/10/20191359
Chrome: From version 79 blocks iframes, scripts, and stylesheets.Chrome Android: From version 79 blocks iframes, scripts, and stylesheets.Edge: From version 79 blocks iframes, scripts, and stylesheets.Quest Browser: From version 8.0 blocks iframes, scripts, and stylesheets.Opera: From version 66 blocks iframes, scripts, and stylesheets.Opera Android: From version 57 blocks iframes, scripts, and stylesheets.Samsung Internet: From version 12.0 blocks iframes, scripts, and stylesheets.WebView Android: From version 79 blocks iframes, scripts, and stylesheets.
http.status.103 📋Chrome6/21/2022 Safari9/18/2023454
Chrome: Supported in HTTP/2 and later only.Chrome Android: Supported in HTTP/2 and later only.Edge: Supported in HTTP/2 and later only.Quest Browser: Supported in HTTP/2 and later only.Opera: Supported in HTTP/2 and later only.Opera Android: Supported in HTTP/2 and later only.Safari: Supported in HTTP/2 and later only.Safari on iOS: Supported in HTTP/2 and later only.Samsung Internet: Supported in HTTP/2 and later only.WebView Android: Supported in HTTP/2 and later only.WebView on iOS: Supported in HTTP/2 and later only.
http.status.103.preconnect Chrome6/21/2022 Safari9/18/2023454
http.status.308 📋Safari10/22/2013 Chrome7/16/2014267
Internet Explorer: Does not work below Windows 10.