Sec-CH-UA-Platform

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

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 HTTP Sec-CH-UA-Platform request header is a user agent client hint which provides the platform or operating system on which the user agent is running. For example: "Windows" or "Android".

Sec-CH-UA-Platform is a low entropy hint. Unless blocked by a user agent permission policy, it is sent by default (without the server opting in by sending Accept-CH).

Header type	Request header, Client hint
Forbidden header name	Yes (`Sec-` prefix)

Syntax

http

Sec-CH-UA-Platform: <platform>

Directives

<platform>: One of the following strings: "Android", "Chrome OS", "Chromium OS", "iOS", "Linux", "macOS", "Windows", or "Unknown".

Examples

Using Sec-CH-UA-Platform

As Sec-CH-UA-Platform is a low entropy hint it is typically sent in all requests. A browser running on a macOS computer might add the following header to all requests.

http

Sec-CH-UA-Platform: "macOS"

Specifications

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

Browser compatibility

BCD tables only load in the browser