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.
Sec-CH-UA-Bitness user agent client hint request header provides the "bitness" of the user-agent's underlying CPU architecture.
This is the size in bits of an integer or memory address—typically 64 or 32 bits.
This might be used by a server, for example, to select and offer the correct binary format of an executable for a user to download.
|Header type||Request header, Client hint|
|Forbidden header name||yes|
A string indicating the underlying platform architecture bitness, such as:
A server requests the
Sec-CH-UA-Bitness 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-Bitness
The client may choose to provide the hint, and add the
Sec-CH-UA-Bitness header to subsequent requests.
For example, on a Windows based 64-bit computer, the client might add the header as shown:
GET /GET /my/page HTTP/1.1 Host: example.site 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-Bitness: "64"
|User-Agent Client Hints |
BCD tables only load in the browser