coderef

User agent client hintsLimited availability

The Sec-CH-UA HTTP request header and the navigator.userAgentData API expose browser and platform information used to vary responses and application logic. User agent client hints are similar to user agent strings but more privacy-preserving and safer to parse.

Not yet supported in all major browsers — check the table and provide a fallback.

How to use ↓Compare browsers

Browser support

DesktopChrome
1–89Not supported
90+Supportedsince Apr 13, 2021
Current: 155
Edge
12–89Not supported
90+Supportedsince Apr 15, 2021
Current: 154
Firefox
✕Not supportedup to 157
Current: 157
Safari
✕Not supportedup to 27
Current: 27
MobileChrome Android
18–89Not supported
90+Supportedsince Apr 13, 2021
Current: 155
Firefox Android
✕Not supportedup to 157
Current: 157
Safari iOS
✕Not supportedup to 27
Current: 27

How to use

Not supported in Firefox, Safari, Firefox Android, Safari iOS. Use feature detection below and provide a fallback (or a polyfill) for those browsers.

Example

Full syntax and examples are on MDN: userAgentData.

Feature detection

JS · check before using
if ("NavigatorUAData" in globalThis) {
  // NavigatorUAData is available
} else {
  // load a polyfill or use a fallback
}

Documentation (MDN)

Specification

Sub-features

Support for each part of the feature (26). The overall table above shows when the whole feature works.

Sub-featureChromeEdgeFirefoxSafariChrome AndroidFirefox AndroidSafari iOS
Navigator.userAgentData9090✕✕90✕✕
Navigator.userAgentData.secure_context_required9090✕✕90✕✕
NavigatorUAData9090✕✕90✕✕
NavigatorUAData.brands9090✕✕90✕✕
NavigatorUAData.getHighEntropyValues9090✕✕90✕✕
NavigatorUAData.mobile9090✕✕90✕✕
NavigatorUAData.platform9393✕✕93✕✕
NavigatorUAData.toJSON9393✕✕93✕✕
WorkerNavigator.userAgentData9090✕✕90✕✕
http.headers.Accept-CH.Sec-CH-UA8989✕✕89✕✕
http.headers.Accept-CH.Sec-CH-UA-Arch8989✕✕89✕✕
http.headers.Accept-CH.Sec-CH-UA-Full-Version8989✕✕89✕✕
http.headers.Accept-CH.Sec-CH-UA-Mobile8989✕✕89✕✕
http.headers.Accept-CH.Sec-CH-UA-Model8989✕✕89✕✕
http.headers.Accept-CH.Sec-CH-UA-Platform8989✕✕89✕✕
http.headers.Accept-CH.Sec-CH-UA-Platform-Version8989✕✕89✕✕
http.headers.Sec-CH-UA8989✕✕89✕✕
http.headers.Sec-CH-UA-Arch8989✕✕89✕✕
http.headers.Sec-CH-UA-Bitness9393✕✕93✕✕
http.headers.Sec-CH-UA-Form-Factors124124✕✕124✕✕
Show 6 more
Sub-featureChromeEdgeFirefoxSafariChrome AndroidFirefox AndroidSafari iOS
http.headers.Sec-CH-UA-Full-Version-List9898✕✕98✕✕
http.headers.Sec-CH-UA-Mobile8989✕✕89✕✕
http.headers.Sec-CH-UA-Model8989✕✕89✕✕
http.headers.Sec-CH-UA-Platform8989✕✕89✕✕
http.headers.Sec-CH-UA-Platform-Version8989✕✕89✕✕
http.headers.Sec-CH-UA-WoW64100100✕✕100✕✕