Sec-CH-UA-Platform header

Limited availability

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

See full compatibility

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 request header	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

	desktop					mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS
`Sec-CH-UA-Platform` request header Experimental	Chrome – Full support Chrome 89 (Release date: 2021-03-02) footnote Full support	Edge – Full support Edge 89 (Release date: 2021-03-04) footnote Full support	Firefox – No support Firefox footnote No support	Opera – Full support Opera 75 (Release date: 2021-03-24) footnote Full support	Safari – No support Safari footnote No support	Chrome Android – Full support Chrome Android 89 (Release date: 2021-03-02) footnote Full support	Firefox for Android – No support Firefox for Android footnote No support	Opera Android – Full support Opera Android 63 (Release date: 2021-04-16) footnote Full support	Safari on iOS – No support Safari on iOS footnote No support	Samsung Internet – Full support Samsung Internet 23 (Release date: 2023-10-18) footnote Full support	WebView Android – Full support WebView Android 89 (Release date: 2021-03-02) footnote Full support	WebView on iOS – No support WebView on iOS footnote No support

Tip: you can click/tap on a cell for more information.

Full support: Full support
No support: No support
: Experimental. Expect behavior to change in the future.