For me it was absolutely surprising that out of the 200 Android apps, only 4 used spaced repetition but beeing an Android developer myself, I took the challenge

For me it was absolutely surprising that out of the 200 Android apps, only 4 used spaced repetition but beeing an Android developer myself, I took the challenge to make it better: https://play.google.com/store/apps/details?id=de.leowandersleb.fluxcards https://play.google.com/store/apps/details?id=de.leowandersl... FluxCards provides spaced repetition learning with easy to edit and create own cards. You can sneak the answer line by line, you can finger-paint and the stats are fast and meaningful. It is free to use with 0.5, 1, 2, 4, 8, 16 days intervals. Beyond that you need the premium version but your cards are yours, so if you consider it not worth the fee, you can export your cards to SD and use them in Anki. And yes, spaced repetition rocks. I can only encourage any flash cards programmer to implement it, as all these apps that implement flash cards but no spaced repetition learning are just not worth your time.