http header

Sec-CH-UA-Mobile header

Limited availabilitySecure context

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](https://developer.mozilla.org/en-US/docs/Glossary/Request%20header), Client hint
[Forbidden request header](https://developer.mozilla.org/en-US/docs/Glossary/Forbidden%20request%20header)	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

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.