Not yet stable

For a given set of browsers, what APIs are not yet in all of them.

Example Comparisons
Browsers
Features

Summary

A count of the number of APIs are in Browser X but not in Browser Y.
Not in FirefoxNot in SafariNot in Edge
In Firefox 289
In Safari 53
In Edge 105122

Unstable APIs

Below is a list of features that are not in all of Firefox, Safari, and Edge

Raw Data

Quick Links:

HTTP Data

API First Browser Date Days in Limbo Notes
http.headers.Accept-CH 📋Edge1/15/20202428
http.headers.Accept-CH.Content-DPR Edge1/15/20202428
http.headers.Accept-CH.DPR Edge1/15/20202428
http.headers.Accept-CH.Device-Memory Edge1/15/20202428
http.headers.Accept-CH.Sec-CH-UA Edge3/4/20212014
http.headers.Accept-CH.Sec-CH-UA-Arch Edge3/4/20212014
http.headers.Accept-CH.Sec-CH-UA-Full-Version Edge3/4/20212014
http.headers.Accept-CH.Sec-CH-UA-Mobile Edge3/4/20212014
http.headers.Accept-CH.Sec-CH-UA-Model Edge3/4/20212014
http.headers.Accept-CH.Sec-CH-UA-Platform Edge3/4/20212014
http.headers.Accept-CH.Sec-CH-UA-Platform-Version Edge3/4/20212014
http.headers.Accept-CH.Viewport-Width Edge1/15/20202428
http.headers.Accept-CH.Width Edge1/15/20202428
http.headers.Access-Control-Allow-Headers.authorization_not_covered_by_wildcard Firefox7/4/20231162
http.headers.Attribution-Reporting-Eligible 📋Edge9/15/20231089
http.headers.Attribution-Reporting-Register-Source 📋Edge9/15/20231089
http.headers.Attribution-Reporting-Register-Trigger 📋Edge9/15/20231089
http.headers.Attribution-Reporting-Support 📋Edge9/15/20231089
http.headers.Authorization.Digest.SHA-256 Firefox10/5/20211799
http.headers.Authorization.authorization_removed_cross_origin 📋Safari10/24/20221415
http.headers.Cache-Control.immutable Firefox9/20/20163640
http.headers.Clear-Site-Data.cache 📋Edge1/15/20202428
http.headers.Clear-Site-Data.clientHints 📋Edge9/15/20231089
http.headers.Content-DPR Edge1/15/20202428
http.headers.Content-Encoding.zstd 📋Edge3/22/2024900
http.headers.Content-Security-Policy.block-all-mixed-content Safari9/20/20163640
Chrome: Will be removed, see bug 40260100.Chrome Android: 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.fenced-frame-src 📋Edge7/21/20231145
http.headers.Content-Security-Policy.form-action.blocks_redirects Safari4/12/20183071
http.headers.Content-Security-Policy.prefetch-src Safari1/23/20231324
http.headers.Content-Security-Policy.require-trusted-types-for 📋Edge5/21/20202301
http.headers.Content-Security-Policy.script-src.inline-speculation-rules 📋Edge2/9/20231307
http.headers.Content-Security-Policy.trusted-types 📋Edge5/21/20202301
http.headers.Critical-CH 📋Edge5/27/20211930
http.headers.Cross-Origin-Embedder-Policy.credentialless 📋Edge11/19/20211754
http.headers.Cross-Origin-Opener-Policy.noopener-allow-popups 📋Edge11/14/2024663
http.headers.DNT Firefox3/22/20115649
http.headers.DPR Edge1/15/20202428
http.headers.Device-Memory 📋Edge1/15/20202428
http.headers.Downlink 📋Edge1/15/20202428
Chrome: The value is never greater than 10 Mbps, as a non-standard anti-fingerprinting measure.Chrome Android: The value is never greater than 10 Mbps, as a non-standard anti-fingerprinting measure.Edge: The value is never greater than 10 Mbps, as a non-standard anti-fingerprinting measure.Quest Browser: The value is never greater than 10 Mbps, as a non-standard anti-fingerprinting measure.Opera: The value is never greater than 10 Mbps, as a non-standard anti-fingerprinting measure.Opera Android: The value is never greater than 10 Mbps, as a non-standard anti-fingerprinting measure.Samsung Internet: The value is never greater than 10 Mbps, as a non-standard anti-fingerprinting measure.WebView Android: The value is never greater than 10 Mbps, as a non-standard anti-fingerprinting measure.
http.headers.ECT 📋Edge1/15/20202428
http.headers.Early-Data 📋Firefox1/23/20183150
http.headers.Expect-CT 📋Edge1/15/20202428
Chrome: Before later builds of Chrome 64, invalid Expect-CT reports would be sent. Newer versions do not send reports after 10 weeks from the build date. See bug 41356303.Chrome Android: Before later builds of Chrome Android 64, invalid Expect-CT reports would be sent. Newer versions do not send reports after 10 weeks from the build date. See bug 41356303.Quest Browser: Before later builds of Quest Browser 5.0, invalid Expect-CT reports would be sent. Newer versions do not send reports after 10 weeks from the build date. See bug 41356303.Opera Android: Before later builds of Opera Android 47, invalid Expect-CT reports would be sent. Newer versions do not send reports after 10 weeks from the build date. See bug 41356303.Samsung Internet: Before later builds of Samsung Internet 9.0, invalid Expect-CT reports would be sent. Newer versions do not send reports after 10 weeks from the build date. See bug 41356303.
http.headers.Link.blocking 📋Edge9/1/20221468
http.headers.Link.expect 📋Edge4/18/2024873
http.headers.NEL 📋Edge1/15/20202428
http.headers.No-Vary-Search 📋Edge7/25/2024775
Chrome: Supported for navigation prefetch cache only.Chrome Android: Supported for navigation prefetch cache only.Edge: Supported for navigation prefetch cache only.Opera: Supported for navigation prefetch cache only.Opera Android: Supported for navigation prefetch cache only.Samsung Internet: Supported for navigation prefetch cache only.WebView Android: Supported for navigation prefetch cache only.
http.headers.Observe-Browsing-Topics Edge7/21/20231145
http.headers.Origin-Agent-Cluster 📋Edge4/15/20211972
http.headers.Permissions-Policy 📋Edge1/21/20212056
http.headers.Permissions-Policy.accelerometer 📋Edge1/15/20202428
http.headers.Permissions-Policy.ambient-light-sensor 📋Edge1/15/20202428
http.headers.Permissions-Policy.attribution-reporting 📋Edge9/15/20231089
http.headers.Permissions-Policy.autoplay 📋Edge1/15/20202428
http.headers.Permissions-Policy.bluetooth 📋Edge8/5/20221495
http.headers.Permissions-Policy.browsing-topics Edge7/21/20231145
http.headers.Permissions-Policy.camera 📋Edge1/15/20202428
http.headers.Permissions-Policy.compute-pressure 📋Edge5/17/2024844
http.headers.Permissions-Policy.cross-origin-isolated 📋Edge11/19/20202119
http.headers.Permissions-Policy.display-capture 📋Edge9/24/20211810
http.headers.Permissions-Policy.document-domain 📋Edge1/15/20202428
http.headers.Permissions-Policy.encrypted-media 📋Edge1/15/20202428
http.headers.Permissions-Policy.fullscreen 📋Edge1/15/20202428
http.headers.Permissions-Policy.geolocation 📋Edge1/15/20202428
http.headers.Permissions-Policy.gyroscope 📋Edge1/15/20202428
http.headers.Permissions-Policy.hid 📋Edge3/4/20212014
http.headers.Permissions-Policy.identity-credentials-get 📋Edge2/9/20231307
http.headers.Permissions-Policy.idle-detection 📋Edge9/24/20211810
http.headers.Permissions-Policy.local-fonts 📋Edge6/23/20221538
http.headers.Permissions-Policy.magnetometer 📋Edge1/15/20202428
http.headers.Permissions-Policy.microphone 📋Edge1/15/20202428
http.headers.Permissions-Policy.midi 📋Edge1/15/20202428
http.headers.Permissions-Policy.otp-credentials 📋Edge9/2/20211832
http.headers.Permissions-Policy.payment 📋Edge1/15/20202428
http.headers.Permissions-Policy.publickey-credentials-create 📋Edge7/16/20202245
http.headers.Permissions-Policy.publickey-credentials-get 📋Edge7/16/20202245
http.headers.Permissions-Policy.screen-wake-lock 📋Edge7/16/20202245
http.headers.Permissions-Policy.serial 📋Edge3/4/20212014
http.headers.Permissions-Policy.storage-access 📋Edge5/5/20231222
http.headers.Permissions-Policy.usb 📋Edge1/15/20202428
http.headers.Permissions-Policy.web-share 📋Edge10/9/20202160
http.headers.Permissions-Policy.wildcards Edge12/5/20221373
http.headers.Permissions-Policy.window-management 📋Edge4/1/20221621
http.headers.Permissions-Policy.xr-spatial-tracking 📋Edge1/15/20202428
http.headers.Priority 📋Edge4/18/2024873
http.headers.RTT 📋Edge1/15/20202428
Chrome: The value is never greater than 3000 ms, as a non-standard anti-fingerprinting measure.Chrome Android: The value is never greater than 3000 ms, as a non-standard anti-fingerprinting measure.Edge: The value is never greater than 3000 ms, as a non-standard anti-fingerprinting measure.Quest Browser: The value is never greater than 3000 ms, as a non-standard anti-fingerprinting measure.Opera: The value is never greater than 3000 ms, as a non-standard anti-fingerprinting measure.Opera Android: The value is never greater than 3000 ms, as a non-standard anti-fingerprinting measure.Samsung Internet: The value is never greater than 3000 ms, as a non-standard anti-fingerprinting measure.WebView Android: The value is never greater than 3000 ms, as a non-standard anti-fingerprinting measure.
http.headers.Referrer-Policy.no-referrer-when-downgrade Edge1/15/20202428
http.headers.Referrer-Policy.origin-when-cross-origin Edge1/15/20202428
http.headers.Referrer-Policy.unsafe-url Edge1/15/20202428
http.headers.Report-To Edge1/15/20202428
http.headers.Reporting-Endpoints 📋Edge11/19/20211754
http.headers.Retry-After 📋Edge10/2/20182898
http.headers.Save-Data 📋Edge1/15/20202428
http.headers.Sec-Browsing-Topics Edge7/21/20231145
http.headers.Sec-CH-Prefers-Color-Scheme 📋Edge9/2/20211832
http.headers.Sec-CH-Prefers-Reduced-Motion 📋Edge12/5/20221373
http.headers.Sec-CH-Prefers-Reduced-Transparency 📋Edge11/2/20231041
http.headers.Sec-CH-UA 📋Edge3/4/20212014
http.headers.Sec-CH-UA-Arch 📋Edge3/4/20212014
http.headers.Sec-CH-UA-Bitness 📋Edge9/2/20211832
http.headers.Sec-CH-UA-Full-Version 📋Edge3/4/20212014
http.headers.Sec-CH-UA-Full-Version-List 📋Edge2/3/20221678
http.headers.Sec-CH-UA-Mobile 📋Edge3/4/20212014
http.headers.Sec-CH-UA-Model 📋Edge3/4/20212014
http.headers.Sec-CH-UA-Platform 📋Edge3/4/20212014
http.headers.Sec-CH-UA-Platform-Version 📋Edge3/4/20212014
http.headers.Sec-Fetch-Dest.fencedframe Edge7/21/20231145
http.headers.Sec-GPC 📋Firefox11/21/20231022
Firefox: Opt-in to GPC using the Website Privacy Preference setting (about:preferences#privacy) checkbox 'Tell websites not to sell or share my data', or by setting the preference privacy.globalprivacycontrol.enabled to true.
http.headers.Sec-Purpose 📋Edge2/9/20231307
http.headers.Sec-Purpose.prefetch Firefox7/4/20231162
Chrome: Doesn't support Sec-Purpose for <link rel="prefetch">. In Chrome, the legacy Purpose: prefetch header is used to indicate a link request is a prefetch. See bug 40236973.Chrome Android: Doesn't support Sec-Purpose for <link rel="prefetch">. In Chrome Android, the legacy Purpose: prefetch header is used to indicate a link request is a prefetch. See bug 40236973.Edge: Doesn't support Sec-Purpose for <link rel="prefetch">. In Edge, the legacy Purpose: prefetch header is used to indicate a link request is a prefetch. See bug 40236973.Firefox: Sec-Purpose: prefetch replaces the non-standard X-moz: prefetch header that was used to indicate a link prefetch request in earlier versions.Firefox: Prefetch requests should also include the header Accept header string for navigations, but Accept: */* is sent instead.Firefox for Android: Sec-Purpose: prefetch replaces the non-standard X-moz: prefetch header that was used to indicate a link prefetch request in earlier versions.Firefox for Android: Prefetch requests should also include the header Accept header string for navigations, but Accept: */* is sent instead.Quest Browser: Doesn't support Sec-Purpose for <link rel="prefetch">. In Quest Browser, the legacy Purpose: prefetch header is used to indicate a link request is a prefetch. See bug 40236973.Opera: Doesn't support Sec-Purpose for <link rel="prefetch">. In Opera, the legacy Purpose: prefetch header is used to indicate a link request is a prefetch. See bug 40236973.Samsung Internet: Doesn't support Sec-Purpose for <link rel="prefetch">. In Samsung Internet, the legacy Purpose: prefetch header is used to indicate a link request is a prefetch. See bug 40236973.WebView Android: Doesn't support Sec-Purpose for <link rel="prefetch">. In WebView Android, the legacy Purpose: prefetch header is used to indicate a link request is a prefetch. See bug 40236973.
http.headers.Sec-Purpose.speculationrules Edge2/9/20231307
http.headers.Server-Timing.trailer Firefox12/10/20192464
Firefox: Only the Server-Timing header is a recognized trailer, and it is only exposed to DevTools in the network Timing tab (bug 1403051). Developers cannot access trailers via the Fetch API or XHR.Firefox for Android: Only the Server-Timing header is a recognized trailer, and it is only exposed to DevTools in the network Timing tab (bug 1403051). Developers cannot access trailers via the Fetch API or XHR.
http.headers.Service-Worker-Navigation-Preload 📋Edge10/2/20182898
http.headers.Set-Cookie.Partitioned 📋Edge6/2/20231194
http.headers.Set-Cookie.SameSite.Lax_default Firefox9/3/20192562
http.headers.Set-Cookie.SameSite.none_requires_secure Edge10/9/20202160
http.headers.Set-Cookie.SameSite.schemeful Firefox7/28/20202233
http.headers.Set-Login 📋Edge12/7/20231006
http.headers.Snapshot-Content-Location Edge1/15/20202428
http.headers.Speculation-Rules 📋Edge1/25/2024957
http.headers.Supports-Loading-Mode 📋Edge1/12/20231335
http.headers.Supports-Loading-Mode.credentialed-prerender Edge1/12/20231335
http.headers.Supports-Loading-Mode.fenced-frames Edge9/15/20231089
http.headers.Trailer 📋Firefox12/10/20192464
Firefox: Only the Server-Timing header is a recognized trailer, and it is only exposed to DevTools in the network Timing tab (bug 1403051). Developers cannot access trailers via the Fetch API or XHR.Firefox for Android: Only the Server-Timing header is a recognized trailer, and it is only exposed to DevTools in the network Timing tab (bug 1403051). Developers cannot access trailers via the Fetch API or XHR.
http.headers.Viewport-Width Edge1/15/20202428
http.headers.WWW-Authenticate.Digest.SHA-256 Firefox10/5/20211799
http.headers.Width Edge1/15/20202428
http.headers.X-DNS-Prefetch-Control Firefox10/24/20067259
http.mixed-content.allow_file_urls 📋Firefox8/6/20134781
http.mixed-content.allow_localhost_url 📋Edge1/15/20202428
http.mixed-content.allow_loopback_url 📋Firefox8/8/20173318
http.mixed-content.auto_upgrade_images 📋Edge10/9/20202160
Firefox: Set security.mixed_content.upgrade_display_content preference to true to allow HTTP fetching and display of upgradable content.Firefox: Set security.mixed_content.block_display_content preference to true to block all mixed content.Firefox for Android: Set security.mixed_content.upgrade_display_content preference to true to allow HTTP fetching and display of upgradable content.Firefox for Android: Set security.mixed_content.block_display_content preference to true to block all mixed content.
http.mixed-content.auto_upgrade_video_audio 📋Edge2/7/20202405
Firefox: Set security.mixed_content.upgrade_display_content preference to true to allow HTTP fetching and display of upgradable content.Firefox: Set security.mixed_content.block_display_content preference to true to block all mixed content.Firefox for Android: Set security.mixed_content.upgrade_display_content preference to true to allow HTTP fetching and display of upgradable content.Firefox for Android: Set security.mixed_content.block_display_content preference to true to block all mixed content.
http.mixed-content.block_mixed_downloads 📋Firefox7/13/20211883
http.mixed-content.private_network_access 📋Edge4/18/2024873
http.status.103.preload Edge6/23/20221538
http.status.425 📋Firefox1/23/20183150