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 ChromeNot in Safari
In Chrome 123
In Safari 3

Unstable APIs

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

Raw Data

Quick Links:

HTTP Data

API First Browser Date Days in Limbo Notes
http.headers.Accept-CH 📋Chrome10/13/20153946
http.headers.Accept-CH.Content-DPR Chrome10/13/20153946
http.headers.Accept-CH.DPR Chrome10/13/20153946
http.headers.Accept-CH.Device-Memory Chrome9/5/20173253
http.headers.Accept-CH.Sec-CH-UA Chrome3/2/20211979
http.headers.Accept-CH.Sec-CH-UA-Arch Chrome3/2/20211979
http.headers.Accept-CH.Sec-CH-UA-Full-Version Chrome3/2/20211979
http.headers.Accept-CH.Sec-CH-UA-Mobile Chrome3/2/20211979
http.headers.Accept-CH.Sec-CH-UA-Model Chrome3/2/20211979
http.headers.Accept-CH.Sec-CH-UA-Platform Chrome3/2/20211979
http.headers.Accept-CH.Sec-CH-UA-Platform-Version Chrome3/2/20211979
http.headers.Accept-CH.Viewport-Width Chrome10/13/20153946
http.headers.Accept-CH.Width Chrome10/13/20153946
http.headers.Attribution-Reporting-Eligible 📋Chrome9/12/20231055
http.headers.Attribution-Reporting-Register-Source 📋Chrome9/12/20231055
http.headers.Attribution-Reporting-Register-Trigger 📋Chrome9/12/20231055
http.headers.Attribution-Reporting-Support 📋Chrome9/12/20231055
http.headers.Authorization.Digest.SHA-256 Chrome9/12/20231055
http.headers.Authorization.authorization_removed_cross_origin 📋Safari10/24/20221378
http.headers.Cache-Control.immutable Safari9/19/20173239
http.headers.Clear-Site-Data.clientHints 📋Chrome9/12/20231055
http.headers.Content-DPR Chrome10/13/20153946
http.headers.Content-Encoding.zstd 📋Chrome3/19/2024866
http.headers.Content-Security-Policy.fenced-frame-src 📋Chrome7/18/20231111
http.headers.Content-Security-Policy.prefetch-src Safari1/23/20231287
http.headers.Content-Security-Policy.require-trusted-types-for 📋Chrome5/19/20202266
http.headers.Content-Security-Policy.script-src.inline-speculation-rules 📋Chrome2/7/20231272
http.headers.Content-Security-Policy.trusted-types 📋Chrome5/19/20202266
http.headers.Critical-CH 📋Chrome5/25/20211895
http.headers.Cross-Origin-Embedder-Policy.credentialless 📋Chrome11/15/20211721
http.headers.Cross-Origin-Opener-Policy.noopener-allow-popups 📋Chrome11/12/2024628
http.headers.DNT Chrome11/6/20125017
http.headers.DPR Chrome10/13/20153946
http.headers.Device-Memory 📋Chrome9/5/20173253
http.headers.Downlink 📋Chrome5/29/20182987
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 📋Chrome5/29/20182987
http.headers.Expect-CT 📋Chrome9/5/20173253
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 📋Chrome9/2/20221430
http.headers.Link.expect 📋Chrome4/16/2024838
http.headers.NEL 📋Chrome12/4/20182798
http.headers.No-Vary-Search 📋Chrome7/23/2024740
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 Chrome7/18/20231111
http.headers.Origin-Agent-Cluster 📋Chrome4/13/20211937
http.headers.Permissions-Policy 📋Chrome1/19/20212021
http.headers.Permissions-Policy.accelerometer 📋Chrome4/17/20183029
http.headers.Permissions-Policy.ambient-light-sensor 📋Chrome4/17/20183029
http.headers.Permissions-Policy.attribution-reporting 📋Chrome9/12/20231055
http.headers.Permissions-Policy.autoplay 📋Chrome1/23/20183113
http.headers.Permissions-Policy.bluetooth 📋Chrome8/2/20221461
http.headers.Permissions-Policy.browsing-topics Chrome7/18/20231111
http.headers.Permissions-Policy.camera 📋Chrome1/23/20183113
http.headers.Permissions-Policy.compute-pressure 📋Chrome5/14/2024810
http.headers.Permissions-Policy.cross-origin-isolated 📋Chrome11/17/20202084
http.headers.Permissions-Policy.display-capture 📋Chrome9/21/20211776
http.headers.Permissions-Policy.document-domain 📋Chrome1/23/20183113
http.headers.Permissions-Policy.encrypted-media 📋Chrome1/23/20183113
http.headers.Permissions-Policy.fullscreen 📋Chrome10/17/20173211
http.headers.Permissions-Policy.geolocation 📋Chrome1/23/20183113
http.headers.Permissions-Policy.gyroscope 📋Chrome4/17/20183029
http.headers.Permissions-Policy.hid 📋Chrome3/2/20211979
http.headers.Permissions-Policy.identity-credentials-get 📋Chrome2/7/20231272
http.headers.Permissions-Policy.idle-detection 📋Chrome9/21/20211776
http.headers.Permissions-Policy.local-fonts 📋Chrome6/21/20221503
http.headers.Permissions-Policy.magnetometer 📋Chrome4/17/20183029
http.headers.Permissions-Policy.microphone 📋Chrome1/23/20183113
http.headers.Permissions-Policy.midi 📋Chrome1/23/20183113
http.headers.Permissions-Policy.otp-credentials 📋Chrome8/31/20211797
http.headers.Permissions-Policy.payment 📋Chrome7/25/20173295
http.headers.Permissions-Policy.picture-in-picture 📋Chrome12/4/20182798
http.headers.Permissions-Policy.publickey-credentials-create 📋Chrome7/27/20202197
http.headers.Permissions-Policy.publickey-credentials-get 📋Chrome7/27/20202197
http.headers.Permissions-Policy.screen-wake-lock 📋Chrome7/27/20202197
http.headers.Permissions-Policy.serial 📋Chrome3/2/20211979
http.headers.Permissions-Policy.storage-access 📋Chrome5/2/20231188
http.headers.Permissions-Policy.usb 📋Chrome7/25/20173295
http.headers.Permissions-Policy.web-share 📋Chrome10/20/20202112
http.headers.Permissions-Policy.wildcards Chrome11/29/20221342
http.headers.Permissions-Policy.window-management 📋Chrome3/29/20221587
http.headers.Permissions-Policy.xr-spatial-tracking 📋Chrome12/10/20192427
http.headers.Priority 📋Chrome4/16/2024838
http.headers.RTT 📋Chrome5/29/20182987
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 Chrome1/25/20173476
http.headers.Referrer-Policy.origin-when-cross-origin Chrome1/25/20173476
http.headers.Referrer-Policy.unsafe-url Chrome1/25/20173476
http.headers.Report-To Chrome10/16/20182847
http.headers.Reporting-Endpoints 📋Chrome11/15/20211721
http.headers.Retry-After 📋Chrome1/10/20134952
http.headers.Save-Data 📋Chrome3/2/20163805
http.headers.Sec-Browsing-Topics Chrome7/18/20231111
http.headers.Sec-CH-Prefers-Color-Scheme 📋Chrome8/31/20211797
http.headers.Sec-CH-Prefers-Reduced-Motion 📋Chrome11/29/20221342
http.headers.Sec-CH-Prefers-Reduced-Transparency 📋Chrome10/31/20231006
http.headers.Sec-CH-UA 📋Chrome3/2/20211979
http.headers.Sec-CH-UA-Arch 📋Chrome3/2/20211979
http.headers.Sec-CH-UA-Bitness 📋Chrome8/31/20211797
http.headers.Sec-CH-UA-Full-Version 📋Chrome3/2/20211979
http.headers.Sec-CH-UA-Full-Version-List 📋Chrome2/1/20221643
http.headers.Sec-CH-UA-Mobile 📋Chrome3/2/20211979
http.headers.Sec-CH-UA-Model 📋Chrome3/2/20211979
http.headers.Sec-CH-UA-Platform 📋Chrome3/2/20211979
http.headers.Sec-CH-UA-Platform-Version 📋Chrome3/2/20211979
http.headers.Sec-Fetch-Dest.fencedframe Chrome7/18/20231111
http.headers.Sec-Purpose 📋Chrome2/7/20231272
http.headers.Sec-Purpose.speculationrules Chrome2/7/20231272
http.headers.Set-Cookie.Partitioned 📋Chrome5/30/20231160
http.headers.Set-Cookie.SameSite.Lax_default Chrome2/4/20202371
http.headers.Set-Cookie.SameSite.none_requires_secure Chrome2/4/20202371
http.headers.Set-Cookie.SameSite.schemeful Chrome5/25/20211895
http.headers.Set-Login 📋Chrome12/5/2023971
http.headers.Snapshot-Content-Location Chrome12/6/20173161
http.headers.Speculation-Rules 📋Chrome1/23/2024922
http.headers.Supports-Loading-Mode 📋Chrome1/10/20231300
http.headers.Supports-Loading-Mode.credentialed-prerender Chrome1/10/20231300
http.headers.Supports-Loading-Mode.fenced-frames Chrome9/12/20231055
http.headers.Viewport-Width Chrome10/13/20153946
http.headers.WWW-Authenticate.Digest.SHA-256 Chrome9/12/20231055
http.headers.Width Chrome10/13/20153946
http.headers.X-DNS-Prefetch-Control Chrome12/11/20086443
http.mixed-content.allow_file_urls 📋Chrome12/10/20192427
http.mixed-content.allow_localhost_url 📋Chrome12/10/20192427
http.mixed-content.allow_loopback_url 📋Chrome12/10/20192427
http.mixed-content.auto_upgrade_images 📋Chrome10/20/20202112
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 📋Chrome2/4/20202371
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 📋Chrome7/20/20211839
http.mixed-content.private_network_access 📋Chrome4/16/2024838
http.status.103.preload Chrome6/21/20221503