User-Agent Reduction on Android WebView

Posted by Mike Taylor (Privacy Sandbox), and Mihai Cîrlănaru (Web on Android)

The User-Agent string has been reduced in Chrome on Desktop and Chrome on Android platforms since Chrome 107. Beginning in Android 16, the default User-Agent string in Android WebView will be similarly reduced.

Updated User-Agent string

The default, reduced WebView User-Agent string is as follows:

Mozilla/5.0 (Linux; Android 10; K; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/125.000 Mobile Safari/537.36

As seen in the diagram, the OS, CPU, and Build information will be reduced to the static “Linux; Android 10; K” string. Minor/build/patch version information is also reduced to “0.0.0” The rest of the default User-Agent remains unchanged (and is unchanging).

How can I detect WebView via the User-Agent string?

Sites can continue to look for the wv token in the User-Agent string, unless an application has decided to override the User-Agent string.

Does WebView support User-Agent Client Hints?

Android WebView has supported User-Agent Client Hints since version 116, but only for applications that send the default User-Agent string.

Will a custom WebView User-Agent string be affected?

The ability to set a custom User-Agent via setUserAgentString() won’t be affected – and applications that choose to do so won’t send the reduced User-Agent string.