index.md

---

title: Accept-CH
slug: Web/HTTP/Headers/Accept-CH
browser-compat: http.headers.Accept-CH

---

{{HTTPSidebar}}{{securecontext_header}}

The Accept-CH header may be set by a server to specify which client hints headers a client should include in subsequent requests.

Header type	{{Glossary("Response header")}}
{{Glossary("Forbidden header name")}}	no
{{Glossary("CORS-safelisted response header")}}	no

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: <comma separated list of client hint headers>

Examples

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

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

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• {{HTTPHeader("Vary")}}