v2026-06-09 rule format supports the requestClientHints behavior v1.0.Client hints are HTTP request header fields that determine which resources the browser should include in the response. This behavior configures and prioritizes the client hints you want to send to request specific client and device information.
Use requestClientHints together with the permissionsPolicy behavior.
| Option | Type | Description | Requires | |
|---|---|---|---|---|
acceptCh |
string array | The client hint data objects you want to receive from the browser. You can add custom entries or provide pre-set values from the list. For more details on each value, see the guide section for this behavior. If you've configured your origin server to pass along data objects, they merge with the ones you set in this array, before the list is sent to the client. Device-Memory Downlink ECT RTT Sec-CH-DPR Sec-CH-UA Sec-CH-UA-Arch Sec-CH-UA-Bitness Sec-CH-UA-Full-Version-List Sec-CH-UA-Mobile Sec-CH-UA-Model Sec-CH-UA-Platform Sec-CH-UA-Platform-Version Sec-CH-Viewport-Width Sec-CH-Width |
{"displayType":"string array","tag":"input","todo":true} | |
acceptCriticalCh |
string array | The critical client hint data objects you want to receive from the browser. The original request from the browser needs to include these objects. Otherwise, a new response header is sent back to the client, asking for all of these client hint data objects. You can add custom entries or provide pre-set values from the list. For more details on each value, see the guide section for this behavior. Device-Memory Downlink ECT RTT Sec-CH-DPR Sec-CH-UA Sec-CH-UA-Arch Sec-CH-UA-Bitness Sec-CH-UA-Full-Version-List Sec-CH-UA-Mobile Sec-CH-UA-Model Sec-CH-UA-Platform Sec-CH-UA-Platform-Version Sec-CH-Viewport-Width Sec-CH-Width |
{"displayType":"string array","tag":"input","todo":true} | |
reset |
boolean | This sends an empty instance of the To enable this option, make sure you leave |
{"displayType":"boolean","tag":"input","type":"checkbox"} |