Accept-CH

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The HTTP Accept-CH response header may be set by a server to specify which client hint headers should be included by the client in subsequent requests. To ensure client hints are sent reliably, the Accept-CH header should be persisted for all secure requests.

Header type Response header
Forbidden header name No
CORS-safelisted response header No

Syntax

http
Accept-CH: <client-hints-headers>

// Client hint headers in a comma-separated list
Accept-CH: <ch-header-one>, <ch-header-two>

Examples

Client hint response headers

The following response headers indicate that the server accepts Viewport-Width and Width device client hints in subsequent requests. The Vary header indicates which values were used to vary the response based on the accepted client hints.

http
Accept-CH: Viewport-Width, Width
Vary: Viewport-Width, Width

Specifications

Specification
HTTP Client Hints
# section-3.1

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Accept-CH client hint accept (response) header
Content-DPR token
DeprecatedNon-standard
DPR token
DeprecatedNon-standard
Device-Memory token
Experimental
Sec-CH-UA token
Experimental
Sec-CH-UA-Arch token
Experimental
Sec-CH-UA-Full-Version token
Experimental
Sec-CH-UA-Mobile token
Experimental
Sec-CH-UA-Model token
Experimental
Sec-CH-UA-Platform token
Experimental
Sec-CH-UA-Platform-Version token
Experimental
Viewport-Width token
DeprecatedNon-standard
Width token
DeprecatedNon-standard

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
No support
No support
Experimental. Expect behavior to change in the future.
Non-standard. Check cross-browser support before using.
Deprecated. Not for use in new websites.

See also