Headers: Sec-CH-UA-Mobile

Sec-CH-UA-Mobile header

Limited availability

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

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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-Mobile request header is a user agent client hint which indicates whether the browser is on a mobile device. It can also be used by a desktop browser to indicate a preference for a "mobile" user experience.

Sec-CH-UA-Mobile 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

Sec-CH-UA-Mobile: <boolean>

Directives

<boolean>: ?1 indicates that the user-agent prefers a mobile experience (true). ?0 indicates that user-agent does not prefer a mobile experience (false).

Examples

Using Sec-CH-UA-Mobile

As Sec-CH-UA-Mobile is a low entropy hint it is typically sent in all requests. A desktop browser would usually send requests with the following header:

Sec-CH-UA-Mobile: ?0

A browser on a mobile device would usually send requests with the following header:

Sec-CH-UA-Mobile: ?1

Specifications

Specification
User-Agent Client Hints> # sec-ch-ua-mobile>

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-Mobile`	89	89	No	75	No	89	No	63	No	23.0	89	No