should be persisted for all
secure requests to ensure client hints are sent reliably.

##  Syntax

http

    
    
    Accept-CH: <comma separated list of client hint headers>
    

##  Examples

http

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

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

##  Specifications

Specification  
---  
[ HTTP Client Hints  
#  section-3.1  ](https://www.rfc-editor.org/rfc/rfc8942#section-3.1)  
  
##  Browser compatibility

BCD tables only load in the browser  with JavaScript enabled. Enable
JavaScript to view data.

##  See also

  * [ ` Vary ` ](/en-US/docs/Web/HTTP/Headers/Vary)

##  Help improve MDN

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](https://github.com/mdn/content/blob/main/CONTRIBUTING.md "This will take you
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This page was last modified on  Apr 29, 2024  by  [ MDN contributors ](/en-
US/docs/Web/HTTP/Headers/Accept-CH/contributors.txt) .

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