I was working on a product which has FSRS implemented, and is heavily inspired by anki. The change we made was that rather than rate yourself, you have to type your answer and its graded by an LLM. It also has a button to explain the concept to you as if you are 5 (eli5) and you get feedback on your answer.
You can also create the flashcards by uploading a pdf and then generate them from it.
I've stopped working on it and am now building something highly similar aimed towards high school students, but any feedback is welcome. This version was built for uni students
mimair.com - I never got around to adding any payment option so its completely free
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