It's built primarily in JavaScript (abcjs, tonaljs, threejs, react), wrapped in React Native for a seamless mobile experience, and uses Keycloak for secure Single Sign-On functionality. The backend is a straightforward ExpressJS setup, focusing on efficiency and scalability, primarily used only for storing and syncing progress.

The app is offline-first, meaning that, for example, on mobile, once you log in, you can use it in flight mode, but once online, it syncs your progress across devices.

For monetization, I'm using subscriptions, and the App is already available on Google Play. If the Android version of the mobile part of the app gains some traction, I'll release it for the App Store as well.

I was motivated by the fact that I could not find a music dictation app that would combine rhythm and melody dictation into melo-rhythmic dictation, which is very important for musicians.

I paid much attention to music entry optimization, so that should be the biggest advantage (apart from there being, as far as I can tell, no rhythm+melody dictation apps on mobile stores). Other than that, I spent a lot of time creating and thinking about curricula; for example, the Pro curriculum has around 90 levels.

If there is interest, I might create a blog post to delve deeper into the features and technical aspects.

Check out the web version of Melo Rhythm here: https://k3y.me Download Melo Rhythm on Google Play : https://play.google.com/store/apps/details?id=com.antiropy.melorhythm

I would be grateful for feedback, suggestions, and discussions from both the Hacker News community and music enthusiasts. Your insights are vital in refining Melo Rhythm and enhancing its impact.