Sec-CH-UA-Mobile Header

Table of Content

The Sec-CH-UA-Mobile header is a type of client hint header that enables the server to understand the mobile-related preferences of the user-agent, by specifying if the user-agent is for a mobile or a desktop device. This allows the server to optimize the content that is sent to the client.


Sec-CH-UA-Mobile: ?0  // For desktop browsers
Sec-CH-UA-Mobile: ?1  // For mobile browsers


The Sec-CH-UA-Mobile header accepts either "?0" or "?1" as directives. "?0" indicates that the user-agent is for a desktop device. On the other hand, "?1" indicates that the user-agent is for a mobile device.


If the user-agent represents a mobile device, the server might receive a request header along these lines:

Sec-CH-UA-Mobile: ?1

On the other hand, if the user-agent represents a desktop device, the request header might look like this:

Sec-CH-UA-Mobile: ?0

Browser Compatibility

Browser Compatibility
Chrome Supported
Firefox Not Supported
Safari Not Supported
Opera Supported
Edge Supported

How to modify Sec-CH-UA-Mobile header

ModHeader is a browser extension that allows users to modify request headers. With ModHeader, you can add, modify, or remove a Sec-CH-UA-Mobile request header. Here's how:

  1. Install the ModHeader browser extension.
  2. On the ModHeader UI, select the "Request headers" tab.
  3. Click on the "+" button to add a new header.
  4. In the "Name" field, type Sec-CH-UA-Mobile.
  5. In the "Value" field, type ?0 or ?1, depending on whether you want the user-agent to represent a desktop or mobile device.

This manipulation is useful, especially during debugging and testing. For example, you can change the Sec-CH-UA-Mobile header to test how your website or web service behaves on both mobile devices and desktops.