This app was born from the desire to learn a few Japanese words, that’s all! It’s not original, there are many similar apps, but it feels more functional than others in its simplicity.
In practice it lets you memorize new words through repetition: as you learn words, they’ll be asked less often, making room for the ones you still haven’t managed to memorize.
Caveat: it doesn’t teach correct pronunciation, and it doesn’t teach you how to write!