Twitter announced on Wednesday that its mobile app now supports physical security keys for iPhone and Android. The company added support for these keys in 2018 but people could only use them in a browser. But switching to the WebAuthn protocol brings the method to mobile devices.
Now anyone with a security key set up on their Twitter account can use that same key to log in from their mobile device, so long as the key is supported. (A ton of security keys exist today that work across different devices, like YubiKeys and Google’s Titan key.)