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 SafariNot in Edge
In Safari 4
In Edge 196

Unstable APIs

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

Raw Data

Quick Links:

HTTP Data

API First Browser Date Days in Limbo Notes
http.headers.Accept-CH 📋Edge1/15/20202334
http.headers.Accept-CH.Content-DPR Edge1/15/20202334
http.headers.Accept-CH.DPR Edge1/15/20202334
http.headers.Accept-CH.Device-Memory Edge1/15/20202334
http.headers.Accept-CH.Sec-CH-DPR 📋Edge1/6/20221612
http.headers.Accept-CH.Sec-CH-Device-Memory 📋Edge1/6/20221612
http.headers.Accept-CH.Sec-CH-UA Edge3/4/20211920
http.headers.Accept-CH.Sec-CH-UA-Arch Edge3/4/20211920
http.headers.Accept-CH.Sec-CH-UA-Full-Version Edge3/4/20211920
http.headers.Accept-CH.Sec-CH-UA-Mobile Edge3/4/20211920
http.headers.Accept-CH.Sec-CH-UA-Model Edge3/4/20211920
http.headers.Accept-CH.Sec-CH-UA-Platform Edge3/4/20211920
http.headers.Accept-CH.Sec-CH-UA-Platform-Version Edge3/4/20211920
http.headers.Accept-CH.Sec-CH-Viewport-Height 📋Edge9/1/20221374
http.headers.Accept-CH.Sec-CH-Viewport-Width 📋Edge1/6/20221612
http.headers.Accept-CH.Sec-CH-Width 📋Edge1/6/20221612
http.headers.Accept-CH.Viewport-Width Edge1/15/20202334
http.headers.Accept-CH.Width Edge1/15/20202334
http.headers.Accept-Encoding.dcb Edge10/17/2024597
http.headers.Accept-Encoding.dcz Edge10/17/2024597
http.headers.Activate-Storage-Access 📋Edge2/6/2025485
http.headers.Attribution-Reporting-Eligible 📋Edge9/15/2023995
http.headers.Attribution-Reporting-Register-Source 📋Edge9/15/2023995
http.headers.Attribution-Reporting-Register-Trigger 📋Edge9/15/2023995
http.headers.Attribution-Reporting-Support 📋Edge9/15/2023995
http.headers.Authorization.Digest.SHA-256 Edge9/15/2023995
http.headers.Authorization.authorization_removed_cross_origin 📋Safari10/24/20221321
http.headers.Available-Dictionary 📋Edge10/17/2024597
http.headers.Cache-Control.immutable Safari9/19/20173182
http.headers.Clear-Site-Data.clientHints 📋Edge9/15/2023995
http.headers.Clear-Site-Data.prefetchCache Edge6/26/2025345
http.headers.Clear-Site-Data.prerenderCache Edge6/26/2025345
http.headers.Content-DPR Edge1/15/20202334
http.headers.Content-Encoding.dcb Edge10/17/2024597
http.headers.Content-Encoding.dcz Edge10/17/2024597
http.headers.Content-Security-Policy.fenced-frame-src 📋Edge6/13/2024723
http.headers.Content-Security-Policy.prefetch-src Safari1/23/20231230
http.headers.Content-Security-Policy.script-src.trusted-types-eval 📋Safari9/15/2025264
http.headers.Critical-CH 📋Edge5/27/20211836
http.headers.Cross-Origin-Embedder-Policy.credentialless 📋Edge11/19/20211660
http.headers.Cross-Origin-Embedder-Policy.report-to_parameter 📋Edge11/19/20211660
http.headers.Cross-Origin-Opener-Policy.report-to_parameter 📋Edge11/19/20211660
http.headers.DNT Edge7/29/20153965
http.headers.DPR Edge1/15/20202334
http.headers.Device-Memory Edge1/15/20202334
Chrome: From Chrome 147, reported values are 2, 4, 8, 16, and 32.Chrome: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Chrome Android: From Chrome 147, reported values are 1, 2, 4, and 8.Chrome Android: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Edge: From Edge 147, reported values are 2, 4, 8, 16, and 32.Edge: Before Edge 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Quest Browser: From Chrome 147, reported values are 1, 2, 4, and 8.Quest Browser: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Opera: From Opera false, reported values are 2, 4, 8, 16, and 32.Opera: Before Opera false, reported values were 0.25, 0.5, 1, 2, 4, and 8.Opera Android: From Chrome 147, reported values are 1, 2, 4, and 8.Opera Android: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Samsung Internet: From Chrome 147, reported values are 1, 2, 4, and 8.Samsung Internet: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.WebView Android: From Chrome 147, reported values are 1, 2, 4, and 8.WebView Android: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.
http.headers.Dictionary-ID 📋Edge10/17/2024597
http.headers.Downlink 📋Edge1/15/20202334
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 📋Edge1/15/20202334
http.headers.Feature-Policy Edge1/15/20202334
http.headers.Feature-Policy.accelerometer 📋Edge1/15/20202334
http.headers.Feature-Policy.ambient-light-sensor 📋Edge1/15/20202334
http.headers.Feature-Policy.attribution-reporting 📋Edge9/15/2023995
http.headers.Feature-Policy.autoplay 📋Edge1/15/20202334
http.headers.Feature-Policy.bluetooth 📋Edge8/5/20221401
http.headers.Feature-Policy.browsing-topics Edge7/21/20231051
http.headers.Feature-Policy.camera 📋Edge1/15/20202334
http.headers.Feature-Policy.compute-pressure 📋Edge5/17/2024750
http.headers.Feature-Policy.cross-origin-isolated 📋Edge11/19/20202025
http.headers.Feature-Policy.deferred-fetch 📋Edge4/4/2025428
http.headers.Feature-Policy.deferred-fetch-minimal 📋Edge4/4/2025428
http.headers.Feature-Policy.display-capture 📋Edge9/24/20211716
http.headers.Feature-Policy.document-domain 📋Edge1/15/20202334
http.headers.Feature-Policy.encrypted-media 📋Edge1/15/20202334
http.headers.Feature-Policy.fullscreen 📋Edge1/15/20202334
http.headers.Feature-Policy.geolocation 📋Edge1/15/20202334
http.headers.Feature-Policy.gyroscope 📋Edge1/15/20202334
http.headers.Feature-Policy.hid 📋Edge3/4/20211920
http.headers.Feature-Policy.identity-credentials-get 📋Edge2/9/20231213
http.headers.Feature-Policy.idle-detection 📋Edge9/24/20211716
http.headers.Feature-Policy.local-fonts 📋Edge6/23/20221444
http.headers.Feature-Policy.magnetometer 📋Edge1/15/20202334
http.headers.Feature-Policy.microphone 📋Edge1/15/20202334
http.headers.Feature-Policy.midi 📋Edge1/15/20202334
http.headers.Feature-Policy.otp-credentials 📋Edge9/2/20211738
http.headers.Feature-Policy.payment 📋Edge1/15/20202334
http.headers.Feature-Policy.picture-in-picture 📋Edge1/15/20202334
http.headers.Feature-Policy.publickey-credentials-create 📋Edge7/16/20202151
http.headers.Feature-Policy.publickey-credentials-get 📋Edge7/16/20202151
http.headers.Feature-Policy.screen-wake-lock 📋Edge7/16/20202151
http.headers.Feature-Policy.serial 📋Edge3/4/20211920
http.headers.Feature-Policy.storage-access 📋Edge5/5/20231128
http.headers.Feature-Policy.usb 📋Edge1/15/20202334
http.headers.Feature-Policy.web-share 📋Edge10/9/20202066
http.headers.Feature-Policy.wildcards Edge12/5/20221279
http.headers.Feature-Policy.window-management 📋Edge4/1/20221527
http.headers.Feature-Policy.xr-spatial-tracking 📋Edge1/15/20202334
http.headers.Integrity-Policy 📋Edge6/26/2025345
Firefox: Reporting endpoints are ignored (violations are logged to console).Firefox for Android: Reporting endpoints are ignored (violations are logged to console).
http.headers.Integrity-Policy.blocked-destinations_script 📋Edge6/26/2025345
http.headers.Integrity-Policy-Report-Only 📋Edge6/26/2025345
Firefox: Reporting endpoints are ignored (violations are logged to console).Firefox for Android: Reporting endpoints are ignored (violations are logged to console).
http.headers.Integrity-Policy-Report-Only.blocked-destinations_script 📋Edge6/26/2025345
http.headers.NEL 📋Edge1/15/20202334
http.headers.No-Vary-Search 📋Edge10/3/2025246
Chrome: Before Chrome 127, speculation rules are only supported for navigational prefetch, not prerender.Chrome: Before Chrome 141, HTTP cache is not supported.Chrome Android: Before Chrome Android 127, speculation rules are only supported for navigational prefetch, not prerender.Chrome Android: Before Chrome Android 141, HTTP cache is not supported.Edge: Before Edge 127, speculation rules are only supported for navigational prefetch, not prerender.Edge: Before Edge 141, HTTP cache is not supported.Opera: Before Opera 113, speculation rules are only supported for navigational prefetch, not prerender.Opera: Before Opera 125, HTTP cache is not supported.Opera Android: Before Opera Android 84, speculation rules are only supported for navigational prefetch, not prerender.Opera Android: Before Opera Android 93, HTTP cache is not supported.Samsung Internet: Before Samsung Internet 28.0, speculation rules are only supported for navigational prefetch, not prerender.Samsung Internet: Before Samsung Internet false, HTTP cache is not supported.WebView Android: Before WebView Android 127, speculation rules are only supported for navigational prefetch, not prerender.WebView Android: Before WebView Android 141, HTTP cache is not supported.
http.headers.No-Vary-Search.http_cache 📋Edge10/3/2025246
http.headers.No-Vary-Search.speculation_rules_prefetch 📋Edge1/25/2024863
http.headers.No-Vary-Search.speculation_rules_prerender 📋Edge7/25/2024681
http.headers.Observe-Browsing-Topics Edge7/21/20231051
http.headers.Origin-Agent-Cluster 📋Edge4/15/20211878
http.headers.Permissions-Policy 📋Edge1/21/20211962
http.headers.Permissions-Policy.accelerometer 📋Edge1/21/20211962
http.headers.Permissions-Policy.ambient-light-sensor 📋Edge1/15/20202334
http.headers.Permissions-Policy.aria-notify Edge10/3/2025246
Chrome: Not supported on ChromeOS.Chrome Android: Not supported on ChromeOS.Edge: Not supported on ChromeOS.Opera: Not supported on ChromeOS.Opera Android: Not supported on ChromeOS.WebView Android: Not supported on ChromeOS.
http.headers.Permissions-Policy.attribution-reporting 📋Edge9/15/2023995
http.headers.Permissions-Policy.autoplay 📋Edge1/21/20211962
http.headers.Permissions-Policy.bluetooth 📋Edge8/5/20221401
http.headers.Permissions-Policy.browsing-topics Edge7/21/20231051
http.headers.Permissions-Policy.camera 📋Edge1/21/20211962
http.headers.Permissions-Policy.captured-surface-control 📋Edge5/1/2025401
http.headers.Permissions-Policy.ch-ua-high-entropy-values 📋Edge1/21/2026136
http.headers.Permissions-Policy.compute-pressure 📋Edge5/17/2024750
http.headers.Permissions-Policy.cross-origin-isolated 📋Edge1/21/20211962
http.headers.Permissions-Policy.deferred-fetch 📋Edge4/4/2025428
http.headers.Permissions-Policy.deferred-fetch-minimal 📋Edge4/4/2025428
http.headers.Permissions-Policy.display-capture 📋Edge9/24/20211716
http.headers.Permissions-Policy.encrypted-media 📋Edge1/21/20211962
http.headers.Permissions-Policy.fullscreen 📋Edge1/21/20211962
http.headers.Permissions-Policy.gamepad 📋Edge6/23/20221444
http.headers.Permissions-Policy.geolocation 📋Edge1/21/20211962
http.headers.Permissions-Policy.gyroscope 📋Edge1/21/20211962
http.headers.Permissions-Policy.hid 📋Edge3/4/20211920
http.headers.Permissions-Policy.identity-credentials-get 📋Edge2/9/20231213
http.headers.Permissions-Policy.idle-detection 📋Edge9/24/20211716
http.headers.Permissions-Policy.local-fonts 📋Edge6/23/20221444
http.headers.Permissions-Policy.magnetometer 📋Edge1/15/20202334
http.headers.Permissions-Policy.microphone 📋Edge1/21/20211962
http.headers.Permissions-Policy.midi 📋Edge1/21/20211962
http.headers.Permissions-Policy.on-device-speech-recognition 📋Edge10/31/2025218
http.headers.Permissions-Policy.otp-credentials 📋Edge9/2/20211738
http.headers.Permissions-Policy.payment 📋Edge1/21/20211962
http.headers.Permissions-Policy.picture-in-picture 📋Edge1/21/20211962
http.headers.Permissions-Policy.private-state-token-issuance 📋Edge9/15/2023995
http.headers.Permissions-Policy.private-state-token-redemption 📋Edge9/15/2023995
http.headers.Permissions-Policy.publickey-credentials-create 📋Edge1/21/20211962
http.headers.Permissions-Policy.publickey-credentials-get 📋Edge1/21/20211962
http.headers.Permissions-Policy.screen-wake-lock 📋Edge1/21/20211962
http.headers.Permissions-Policy.serial 📋Edge3/4/20211920
http.headers.Permissions-Policy.storage-access 📋Edge5/5/20231128
http.headers.Permissions-Policy.summarizer 📋Edge6/26/2025345
http.headers.Permissions-Policy.usb 📋Edge1/21/20211962
http.headers.Permissions-Policy.web-share 📋Edge1/21/20211962
http.headers.Permissions-Policy.wildcards Edge12/5/20221279
http.headers.Permissions-Policy.window-management 📋Edge4/1/20221527
http.headers.Permissions-Policy.xr-spatial-tracking 📋Edge1/21/20211962
http.headers.Priority 📋Edge4/18/2024779
http.headers.RTT 📋Edge1/15/20202334
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 Edge1/15/20202334
http.headers.Referrer-Policy.origin-when-cross-origin Edge1/15/20202334
http.headers.Referrer-Policy.unsafe-url Edge1/15/20202334
http.headers.Report-To Edge1/15/20202334
http.headers.Retry-After 📋Edge10/2/20182804
http.headers.Save-Data 📋Edge1/15/20202334
http.headers.Sec-Browsing-Topics Edge7/21/20231051
http.headers.Sec-CH-DPR 📋Edge1/6/20221612
http.headers.Sec-CH-Device-Memory 📋Edge1/6/20221612
Chrome: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Chrome: From Chrome 147, reported values are 2, 4, 8, 16, and 32.Chrome: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Chrome: From Chrome 147, reported values are 2, 4, 8, 16, and 32.Chrome Android: From Chrome 147, reported values are 1, 2, 4, and 8.Chrome Android: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Chrome Android: From Chrome 147, reported values are 1, 2, 4, and 8.Chrome Android: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Edge: Before Edge 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Edge: From Edge 147, reported values are 2, 4, 8, 16, and 32.Edge: Before Edge 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Edge: From Edge 147, reported values are 2, 4, 8, 16, and 32.Quest Browser: From Chrome 147, reported values are 1, 2, 4, and 8.Quest Browser: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Quest Browser: From Chrome 147, reported values are 1, 2, 4, and 8.Quest Browser: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Opera: Before Opera false, reported values were 0.25, 0.5, 1, 2, 4, and 8.Opera: From Opera false, reported values are 2, 4, 8, 16, and 32.Opera: Before Opera false, reported values were 0.25, 0.5, 1, 2, 4, and 8.Opera: From Opera false, reported values are 2, 4, 8, 16, and 32.Opera Android: From Chrome 147, reported values are 1, 2, 4, and 8.Opera Android: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Opera Android: From Chrome 147, reported values are 1, 2, 4, and 8.Opera Android: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Samsung Internet: From Chrome 147, reported values are 1, 2, 4, and 8.Samsung Internet: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.Samsung Internet: From Chrome 147, reported values are 1, 2, 4, and 8.Samsung Internet: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.WebView Android: From Chrome 147, reported values are 1, 2, 4, and 8.WebView Android: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.WebView Android: From Chrome 147, reported values are 1, 2, 4, and 8.WebView Android: Before Chrome 147, reported values were 0.25, 0.5, 1, 2, 4, and 8.
http.headers.Sec-CH-Prefers-Color-Scheme 📋Edge9/2/20211738
http.headers.Sec-CH-Prefers-Reduced-Motion 📋Edge12/5/20221279
http.headers.Sec-CH-Prefers-Reduced-Transparency 📋Edge11/2/2023947
http.headers.Sec-CH-UA 📋Edge3/4/20211920
http.headers.Sec-CH-UA-Arch 📋Edge3/4/20211920
http.headers.Sec-CH-UA-Bitness 📋Edge9/2/20211738
http.headers.Sec-CH-UA-Form-Factors 📋Edge4/18/2024779
http.headers.Sec-CH-UA-Full-Version 📋Edge3/4/20211920
http.headers.Sec-CH-UA-Full-Version-List 📋Edge2/3/20221584
http.headers.Sec-CH-UA-Mobile 📋Edge3/4/20211920
http.headers.Sec-CH-UA-Model 📋Edge3/4/20211920
http.headers.Sec-CH-UA-Platform 📋Edge3/4/20211920
http.headers.Sec-CH-UA-Platform-Version 📋Edge3/4/20211920
http.headers.Sec-CH-UA-WoW64 📋Edge4/1/20221527
http.headers.Sec-CH-Viewport-Height 📋Edge9/1/20221374
http.headers.Sec-CH-Viewport-Width 📋Edge1/6/20221612
http.headers.Sec-CH-Width 📋Edge1/6/20221612
http.headers.Sec-Fetch-Dest.fencedframe Edge6/13/2024723
http.headers.Sec-Fetch-Storage-Access 📋Edge2/6/2025485
http.headers.Sec-Fetch-User 📋Edge1/15/20202334
http.headers.Sec-Private-State-Token 📋Edge9/15/2023995
http.headers.Sec-Private-State-Token-Crypto-Version 📋Edge9/15/2023995
http.headers.Sec-Private-State-Token-Lifetime 📋Edge9/15/2023995
http.headers.Sec-Purpose 📋Edge2/9/20231213
http.headers.Sec-Redemption-Record 📋Edge9/15/2023995
http.headers.Set-Cookie.SameSite.Lax_default Edge10/9/20202066
http.headers.Set-Cookie.SameSite.none_requires_secure Edge10/9/20202066
http.headers.Set-Cookie.SameSite.schemeful Edge5/27/20211836
http.headers.Set-Cookie.http_host-http_prefixes Edge9/5/2025274
Firefox: __Host-Http- is supported under its original name __HostHttp-. See bug 1982555.Firefox for Android: __Host-Http- is supported under its original name __HostHttp-. See bug 1982555.
http.headers.Set-Login 📋Edge12/7/2023912
http.headers.Snapshot-Content-Location Edge1/15/20202334
http.headers.Supports-Loading-Mode 📋Edge1/12/20231241
http.headers.Supports-Loading-Mode.credentialed-prerender 📋Edge1/12/20231241
http.headers.Supports-Loading-Mode.fenced-frame 📋Edge9/15/2023995
http.headers.Use-As-Dictionary 📋Edge10/17/2024597
http.headers.Viewport-Width Edge1/15/20202334
http.headers.WWW-Authenticate.Digest.SHA-256 Edge9/15/2023995
http.headers.Width Edge1/15/20202334
http.headers.X-DNS-Prefetch-Control Edge1/15/20202334
http.mixed-content.allow_file_urls 📋Edge1/15/20202334
http.mixed-content.allow_localhost_url 📋Edge1/15/20202334
http.mixed-content.allow_loopback_url 📋Edge1/15/20202334
http.mixed-content.auto_upgrade_images 📋Edge10/9/20202066
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 📋Edge2/7/20202311
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 📋Edge7/22/20211780
http.mixed-content.private_network_access 📋Edge6/26/2025345
http.status.103.preload Edge6/23/20221444