Sec,ch,ua,mobile:,?0 Apr 2026

The header sec-ch-ua-mobile: ?0 is a that tells a web server the request is coming from a desktop device .

: Include interactive elements that rely on mouse-hover actions, which don't exist on touchscreens.

: Serve expansive, multi-column designs rather than single-column mobile stacks. sec,ch,ua,mobile:,?0

: It is part of the Privacy Sandbox initiative to reduce the information leaked by traditional "User-Agent" strings.

The ?0 value is a boolean indicator where 0 means "false" (not a mobile device). If you are "drafting proper content" based on this header, your server-side logic should prioritize and features. Content Strategy for ?0 (Desktop) The header sec-ch-ua-mobile:

: Deliver larger images or background videos that might be too heavy for mobile data connections.

: It is a "low-entropy" hint, meaning browsers like Chrome send it by default on every secure (HTTPS) request without the server needing to ask for it. : It is part of the Privacy Sandbox

When a server identifies a user as desktop-based via this header, you should deliver: