Accept-CH

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

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The Accept-CH header is set by the server to specify which Client Hints headers client should include in subsequent requests.

Header type Response header
Forbidden header name ?

Note: Client Hints are accessible only on secure origins (via TLS). Accept-CH and Accept-CH-Lifetime headers should be persisted for all secure requests to ensure Client Hints are sent reliably.

Syntax

Accept-CH: <list of client hints>

Examples

Accept-CH: DPR, Viewport-Width
Accept-CH: Width
Accept-CH-Lifetime: 86400
Vary: DPR, Viewport-Width, Width

Note: Remember to vary the response based on the accepted client hints.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Accept-CHChrome Full support 46Edge ? Firefox ? IE ? Opera Full support 33Safari ? WebView Android Full support 46Chrome Android Full support 46Firefox Android ? Opera Android Full support 33Safari iOS ? Samsung Internet Android Full support Yes
DPR
ExperimentalNon-standard
Chrome Full support 46Edge ? Firefox ? IE ? Opera Full support 33Safari ? WebView Android Full support 46Chrome Android Full support 46Firefox Android ? Opera Android Full support 33Safari iOS ? Samsung Internet Android Full support Yes
Viewport-Width
ExperimentalNon-standard
Chrome Full support 46Edge ? Firefox ? IE ? Opera Full support 33Safari ? WebView Android Full support 46Chrome Android Full support 46Firefox Android ? Opera Android Full support 33Safari iOS ? Samsung Internet Android Full support Yes
Width
ExperimentalNon-standard
Chrome Full support 46Edge ? Firefox ? IE ? Opera Full support 33Safari ? WebView Android Full support 46Chrome Android Full support 46Firefox Android ? Opera Android Full support 33Safari iOS ? Samsung Internet Android Full support Yes

Legend

Full support  
Full support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
Non-standard. Expect poor cross-browser support.
Non-standard. Expect poor cross-browser support.

See also