by Juan Leyva.
Hi,
you have our developer documentation here: https://docs.moodle.org/dev/Moodle_Mobile
Please, notice that right now if you want to build a custom addon for the app you will have to build your custom app, we are working in a new improvement in the app to support addons without having to build a custom app. In any case, the required changes between the first and second approach will be minimum
Juan