HSKLord
HSKLord teaches Chinese vocabulary for the HSK exams using spaced repetition, across a web app and native builds for iOS and Android.
I founded it and nobody else has worked on it. The web app, both mobile builds, the review scheduler and the subscription layer are mine, and so is the release pipeline that puts them in the stores.
Both store listings are live and public with my own legal name as the seller, and the app has paying subscribers.