Yes we have an app on iOS and Android. Just search for NauticEd - or see all our apps here:

Currently, as of January 2023 we are rebuilding the Android App as Google made some changes to the required architecture which make our App crash - sorry.

We do recommend that you use a browser online either on your mobile device or computer when possible purely because the pages are all mobile friendly and they are better optimized for browser. The tests, whether on app or browser, are connected to the same database so it makes no difference how you take the test.