---
title: Accept-CH
slug: Web/HTTP/Headers/Accept-CH
tags:
  - Accept-CH
  - Client hints
  - HTTP
  - HTTP Header
  - Response header
browser-compat: http.headers.Accept-CH
---
{{HTTPSidebar}}{{securecontext_header}}{{SeeCompatTable}}

The **`Accept-CH`** header may be set by a server to specify
which [client hints](/en-US/docs/Glossary/Client_hints) headers a client
should include in subsequent requests.

<table class="properties">
  <tbody>
    <tr>
      <th scope="row">Header type</th>
      <td>{{Glossary("Response header")}}</td>
    </tr>
    <tr>
      <th scope="row">{{Glossary("Forbidden header name")}}</th>
      <td>no</td>
    </tr>
    <tr>
      <th scope="row">
        {{Glossary("CORS-safelisted response header")}}
      </th>
      <td>no</td>
    </tr>
  </tbody>
</table>

> **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: Viewport-Width, Width
    Vary: Viewport-Width, Width

> **Note:** Remember to [vary the response](/en-US/docs/Glossary/Client_hints#varying_client_hints)
> based on the accepted client hints.

## Specifications

{{Specifications}}

## Browser compatibility

{{Compat}}

## See also

- {{HTTPHeader("Vary")}}
