True just checked, they didn't made an app yet, it's still "only" an extension 🤙
Hope it will be soon 🍀 

 Although there is not a native app, there is a PWA, and you can use it with NWC to connect to Amethyst and other Nostr mobile apps.

Checkout our user guides: 
https://guides.getalby.com/user-guide

Here are other apps to discover that can be connected to Alby:
https://getalby.com/discover

Thank you for your interest!
-JP 

 Thanks but the requirement for now is an APK

Support for PWAs will come, though!