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

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

The Sec-CH-UA-Platform-Version user agent client hint request header provides the version of the operating system on which the user agent is running.

Header type Request header, Client hint
Forbidden header name yes


Sec-CH-UA-Platform-Version: <version>



The version string typically contains the operating system version in a string, consisting of dot-separated major, minor and patch version numbers. For example, "11.0.0"

The version string on Linux is always empty.


A server requests the Sec-CH-UA-Platform-Version header by including the Accept-CH in a response to any request from the client, using the name of the desired header as a token:

HTTP/1.1 200 OK
Accept-CH: Sec-CH-UA-Platform-Version

The client may choose to provide the hint, and add the Sec-CH-UA-Platform-Version header to subsequent requests. For example, the following request headers might be sent from a browser running on Windows 10.

GET /GET /my/page HTTP/1.1

Sec-CH-UA: " Not A;Brand";v="99", "Chromium";v="96", "Google Chrome";v="96"
Sec-CH-UA-Mobile: ?0
Sec-CH-UA-Platform: "Windows"
Sec-CH-UA-Platform-Version: "10.0.0"


User-Agent Client Hints
# sec-ch-ua-platform-version

Browser compatibility

BCD tables only load in the browser

See also