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 SafariLast in Safari on iOS
First in Safari 151
First in Safari on iOS 30

Average time for an API to become available across Safari and Safari on iOS

181 APIs took an average of 505.33 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 Safari and Safari on iOS). TTA (time to available).
HTTP APIsHTTP TTA
2003 581467.00
2008 4115.00
2009 10299.00
2010 291.00
2012 547.00
2013 2134.00
2016 893.25
2017 80.00
2018 10105.20
2019 70.00
2020 30.00
2021 30.00
2022 120.00
2023 180.00
2025 100.00
2026 20.00

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 Safari and Safari on iOS. TTA (time to available).
Year HTTPHTTP TTA
2003
  Safari 581467.00
2008
  Safari 4115.00
2009
  Safari 10299.00
2010
  Safari 291.00
2012
  Safari 547.00
2013
  Safari on iOS 2134.00
2016
  Safari on iOS 6124.33
  Safari 20.00
2017
  Safari 80.00
2018
  Safari on iOS 314.00
  Safari 7144.29
2019
  Safari 70.00
2020
  Safari 30.00
2021
  Safari 30.00
2022
  Safari 120.00
2023
  Safari 180.00
2025
  Safari 100.00
2026
  Safari 20.00

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 Safari and Safari on iOS. TTA (time to available).
Year HTTP countHTTP TTA
2003
  Safari on iOS 581467.00
2008
  Safari on iOS 4115.00
2009
  Safari on iOS 10299.00
2010
  Safari on iOS 291.00
2012
  Safari on iOS 547.00
2013
  Safari 2134.00
2016
  Safari 6124.33
  Safari on iOS 20.00
2017
  Safari on iOS 80.00
2018
  Safari 314.00
  Safari on iOS 7144.29
2019
  Safari on iOS 70.00
2020
  Safari on iOS 30.00
2021
  Safari on iOS 30.00
2022
  Safari on iOS 120.00
2023
  Safari on iOS 180.00
2025
  Safari on iOS 100.00
2026
  Safari on iOS 20.00

Stable APIs

Below is a list of features that are in Safari and Safari on iOS

Raw Data

Quick Links:

HTTP Data

API First Browser Date Last Browser Date Days Notes
http.data-url 📋Safari3/18/2008 Safari on iOS7/11/2008115
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 Safari on iOS7/11/2008115
http.data-url.html_files Safari3/18/2008 Safari on iOS7/11/2008115
http.data-url.js_files Safari3/18/2008 Safari on iOS7/11/2008115
http.data-url.top_level_navigation_blocked Safari9/16/2020 Safari on iOS9/16/2020
http.headers.Accept 📋Safari6/23/2003 Safari on iOS6/29/20071467
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 Safari on iOS6/29/20071467
http.headers.Accept-Encoding.br 📋Safari9/19/2017 Safari on iOS9/19/2017
Safari: Unsupported before macOS 10.13 High Sierra.
http.headers.Accept-Encoding.zstd 📋Safari2/11/2026 Safari on iOS2/11/2026
Safari: Before macOS 26.3 Tahoe, this header value is not sent.
http.headers.Accept-Language 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Accept-Ranges 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Access-Control-Allow-Credentials 📋Safari6/8/2009 Safari on iOS4/3/2010299
http.headers.Access-Control-Allow-Headers 📋Safari6/8/2009 Safari on iOS4/3/2010299
http.headers.Access-Control-Allow-Headers.wildcard Safari9/19/2019 Safari on iOS9/19/2019
http.headers.Access-Control-Allow-Methods 📋Safari6/8/2009 Safari on iOS4/3/2010299
http.headers.Access-Control-Allow-Methods.wildcard Safari9/19/2019 Safari on iOS9/19/2019
http.headers.Access-Control-Allow-Origin 📋Safari6/8/2009 Safari on iOS4/3/2010299
http.headers.Access-Control-Expose-Headers 📋Safari6/8/2009 Safari on iOS4/3/2010299
http.headers.Access-Control-Expose-Headers.wildcard Safari9/19/2019 Safari on iOS9/19/2019
http.headers.Access-Control-Max-Age 📋Safari6/8/2009 Safari on iOS4/3/2010299
http.headers.Access-Control-Request-Headers 📋Safari6/8/2009 Safari on iOS4/3/2010299
http.headers.Access-Control-Request-Method 📋Safari6/8/2009 Safari on iOS4/3/2010299
http.headers.Age 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Alt-Svc 📋Safari9/18/2023 Safari on iOS9/18/2023
Firefox: Only supports draft-04Firefox for Android: Only supports draft-04
http.headers.Authorization 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Authorization.Basic 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Authorization.Digest 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Authorization.Digest.md5 Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Authorization.NTLM Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Authorization.Negotiate 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Authorization.authorization_removed_cross_origin 📋Safari10/24/2022 Safari on iOS10/24/2022
http.headers.Cache-Control 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Cache-Control.immutable Safari9/19/2017 Safari on iOS9/19/2017
http.headers.Cache-Control.stale-while-revalidate 📋Safari9/16/2020 Safari on iOS9/16/2020
http.headers.Clear-Site-Data 📋Safari9/18/2023 Safari on iOS9/18/2023
http.headers.Clear-Site-Data.cache 📋Safari9/18/2023 Safari on iOS9/18/2023
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 📋Safari9/18/2023 Safari on iOS9/18/2023
http.headers.Clear-Site-Data.secure_context_required Safari9/18/2023 Safari on iOS9/18/2023
http.headers.Clear-Site-Data.storage 📋Safari9/18/2023 Safari on iOS9/18/2023
http.headers.Clear-Site-Data.wildcard 📋Safari9/18/2023 Safari on iOS9/18/2023
http.headers.Connection 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Content-Disposition 📋Safari6/23/2003 Safari on iOS6/29/20071467
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 Safari on iOS6/29/20071467
http.headers.Content-Encoding.br 📋Safari9/19/2017 Safari on iOS9/19/2017
Safari: Unsupported before macOS 10.13 High Sierra.
http.headers.Content-Encoding.zstd 📋Safari2/11/2026 Safari on iOS2/11/2026
Safari: Before macOS 26.3 Tahoe, Safari cannot decode Zstandard responses.
http.headers.Content-Language 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Content-Length 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Content-Length.cors_response_safelist Safari3/25/2019 Safari on iOS3/25/2019
http.headers.Content-Location 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Content-Range 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Content-Security-Policy 📋Safari on iOS9/18/2013 Safari10/22/201334
Internet Explorer: Only supporting 'sandbox' directive.
http.headers.Content-Security-Policy.base-uri 📋Safari on iOS3/21/2016 Safari9/20/2016183
http.headers.Content-Security-Policy.block-all-mixed-content Safari on iOS9/13/2016 Safari9/20/20167
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 📋Safari on iOS3/21/2016 Safari9/20/2016183
http.headers.Content-Security-Policy.connect-src 📋Safari on iOS9/18/2013 Safari10/22/201334
Firefox: Before Firefox 50, ping attributes of <a> elements weren't covered by connect-src.
http.headers.Content-Security-Policy.default-src 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Content-Security-Policy.font-src 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Content-Security-Policy.form-action 📋Safari on iOS3/21/2016 Safari9/20/2016183
http.headers.Content-Security-Policy.form-action.blocks_redirects Safari on iOS3/29/2018 Safari4/12/201814
http.headers.Content-Security-Policy.frame-ancestors 📋Safari on iOS3/21/2016 Safari9/20/2016183
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 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Content-Security-Policy.img-src 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Content-Security-Policy.manifest-src 📋Safari9/19/2017 Safari on iOS9/19/2017
http.headers.Content-Security-Policy.media-src 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Content-Security-Policy.meta-element-support Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Content-Security-Policy.object-src 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Content-Security-Policy.prefetch-src Safari1/23/2023 Safari on iOS1/23/2023
http.headers.Content-Security-Policy.report-sample Safari3/14/2022 Safari on iOS3/14/2022
http.headers.Content-Security-Policy.report-to 📋Safari3/27/2023 Safari on iOS3/27/2023
http.headers.Content-Security-Policy.report-uri 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Content-Security-Policy.require-trusted-types-for 📋Safari9/15/2025 Safari on iOS9/15/2025
http.headers.Content-Security-Policy.sandbox 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Content-Security-Policy.script-src 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Content-Security-Policy.script-src.external_scripts 📋Safari7/20/2022 Safari on iOS7/20/2022
http.headers.Content-Security-Policy.script-src.inline-speculation-rules Safari12/12/2025 Safari on iOS12/12/2025
http.headers.Content-Security-Policy.script-src.trusted-types-eval 📋Safari9/15/2025 Safari on iOS9/15/2025
http.headers.Content-Security-Policy.script-src.wasm-unsafe-eval Safari9/12/2022 Safari on iOS9/12/2022
http.headers.Content-Security-Policy.script-src-attr 📋Safari3/14/2022 Safari on iOS3/14/2022
http.headers.Content-Security-Policy.script-src-elem 📋Safari3/14/2022 Safari on iOS3/14/2022
http.headers.Content-Security-Policy.strict-dynamic Safari3/14/2022 Safari on iOS3/14/2022
http.headers.Content-Security-Policy.style-src 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Content-Security-Policy.style-src-attr 📋Safari3/14/2022 Safari on iOS3/14/2022
http.headers.Content-Security-Policy.style-src-elem 📋Safari12/12/2025 Safari on iOS12/12/2025
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 📋Safari9/15/2025 Safari on iOS9/15/2025
http.headers.Content-Security-Policy.unsafe-hashes Safari3/14/2022 Safari on iOS3/14/2022
http.headers.Content-Security-Policy.upgrade-insecure-requests 📋Safari3/27/2017 Safari on iOS3/27/2017
http.headers.Content-Security-Policy.worker-src 📋Safari5/16/2022 Safari on iOS5/16/2022
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 Safari on iOS9/13/2016 Safari9/20/20167
http.headers.Content-Security-Policy-Report-Only 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Content-Type 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Cookie 📋Safari6/23/2003 Safari on iOS6/29/20071467
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 📋Safari12/13/2021 Safari on iOS12/13/2021
http.headers.Cross-Origin-Opener-Policy 📋Safari12/13/2021 Safari on iOS12/13/2021
http.headers.Cross-Origin-Opener-Policy.noopener-allow-popups 📋Safari3/31/2025 Safari on iOS3/31/2025
http.headers.Cross-Origin-Resource-Policy 📋Safari9/17/2018 Safari on iOS9/17/2018
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 Safari on iOS6/29/20071467
http.headers.ETag 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Expires 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.From 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Host 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.If-Match 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.If-Modified-Since 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.If-None-Match 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.If-Range 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.If-Unmodified-Since 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Keep-Alive 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Last-Modified 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Link 📋Safari9/18/2023 Safari on iOS9/18/2023
http.headers.Link.fetchpriority 📋Safari12/11/2023 Safari on iOS12/11/2023
http.headers.Location 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Origin 📋Safari6/23/2003 Safari on iOS6/29/20071467
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 Safari on iOS6/29/20071467
http.headers.Proxy-Authenticate 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Range 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Range.cors_safe Safari9/12/2022 Safari on iOS9/12/2022
http.headers.Referer 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Referer.length_limit_4096B Safari9/16/2020 Safari on iOS9/16/2020
http.headers.Referrer-Policy 📋Safari4/12/2018 Safari on iOS9/17/2018158
http.headers.Referrer-Policy.default_strict-origin-when-cross-origin Safari9/20/2021 Safari on iOS9/20/2021
http.headers.Referrer-Policy.same-origin Safari4/12/2018 Safari on iOS9/17/2018158
http.headers.Referrer-Policy.strict-origin Safari4/12/2018 Safari on iOS9/17/2018158
http.headers.Referrer-Policy.strict-origin-when-cross-origin Safari4/12/2018 Safari on iOS9/17/2018158
http.headers.Refresh 📋Safari6/23/2003 Safari on iOS6/29/20071467
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 📋Safari3/27/2023 Safari on iOS3/27/2023
http.headers.Sec-Fetch-Dest 📋Safari3/27/2023 Safari on iOS3/27/2023
http.headers.Sec-Fetch-Mode 📋Safari3/27/2023 Safari on iOS3/27/2023
http.headers.Sec-Fetch-Site 📋Safari3/27/2023 Safari on iOS3/27/2023
http.headers.Sec-Purpose.speculationrules Safari12/12/2025 Safari on iOS12/12/2025
http.headers.Sec-Speculation-Tags 📋Safari12/12/2025 Safari on iOS12/12/2025
http.headers.Sec-WebSocket-Accept 📋Safari7/25/2012 Safari on iOS9/10/201247
http.headers.Sec-WebSocket-Extensions 📋Safari7/25/2012 Safari on iOS9/10/201247
http.headers.Sec-WebSocket-Key 📋Safari7/25/2012 Safari on iOS9/10/201247
http.headers.Sec-WebSocket-Protocol 📋Safari7/25/2012 Safari on iOS9/10/201247
http.headers.Sec-WebSocket-Version 📋Safari7/25/2012 Safari on iOS9/10/201247
http.headers.Server 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Server-Timing 📋Safari3/27/2023 Safari on iOS3/27/2023
http.headers.Service-Worker 📋Safari on iOS3/29/2018 Safari4/12/201814
http.headers.Service-Worker-Allowed 📋Safari on iOS3/29/2018 Safari4/12/201814
http.headers.Service-Worker-Navigation-Preload 📋Safari3/14/2022 Safari on iOS3/14/2022
http.headers.Set-Cookie 📋Safari6/23/2003 Safari on iOS6/29/20071467
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 Safari6/7/2010 Safari on iOS6/21/201014
http.headers.Set-Cookie.Max-Age Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Set-Cookie.Partitioned 📋Safari12/12/2025 Safari on iOS12/12/2025
http.headers.Set-Cookie.SameSite 📋Safari9/19/2019 Safari on iOS9/19/2019
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 Safari9/17/2018 Safari on iOS3/25/2019189
http.headers.Set-Cookie.SameSite.None Safari9/19/2019 Safari on iOS9/19/2019
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 Safari9/17/2018 Safari on iOS3/25/2019189
http.headers.Set-Cookie.host_secure_prefixes Safari9/19/2019 Safari on iOS9/19/2019
http.headers.SourceMap 📋Safari on iOS9/18/2013 Safari10/22/201334
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 📋Safari12/12/2025 Safari on iOS12/12/2025
http.headers.Strict-Transport-Security 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.TE 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Timing-Allow-Origin 📋Safari9/19/2017 Safari on iOS9/19/2017
http.headers.Transfer-Encoding 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Upgrade 📋Safari6/7/2010 Safari on iOS11/22/2010168
http.headers.Upgrade-Insecure-Requests 📋Safari3/27/2017 Safari on iOS3/27/2017
http.headers.User-Agent 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Vary 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.Via 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.WWW-Authenticate 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.WWW-Authenticate.Basic 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.WWW-Authenticate.Digest 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.WWW-Authenticate.Digest.md5 Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.WWW-Authenticate.NTLM Safari on iOS9/18/2013 Safari10/22/201334
http.headers.WWW-Authenticate.Negotiate 📋Safari on iOS9/18/2013 Safari10/22/201334
http.headers.Warning 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.headers.X-Content-Type-Options 📋Safari9/19/2017 Safari on iOS9/19/2017
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 Safari on iOS4/3/2010299
http.headers.X-Frame-Options.SAMEORIGIN Safari6/8/2009 Safari on iOS4/3/2010299
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 Safari on iOS6/29/20071467
http.methods.DELETE 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.methods.GET 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.methods.HEAD 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.methods.OPTIONS 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.methods.POST 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.methods.PUT 📋Safari6/23/2003 Safari on iOS6/29/20071467
http.mixed-content 📋Safari3/21/2016 Safari on iOS3/21/2016
http.mixed-content.blockable_mixed_content 📋Safari3/21/2016 Safari on iOS3/21/2016
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 📋Safari9/18/2023 Safari on iOS9/18/2023
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 Safari9/18/2023 Safari on iOS9/18/2023
http.status.308 📋Safari on iOS9/18/2013 Safari10/22/201334
Internet Explorer: Does not work below Windows 10.