Knowt makes the cards. Synapsi makes sure you learned them.
Knowt is a great free way to turn notes and PDFs into flashcards. Synapsi does that too, then adds the part Knowt skips: an AI-judged Feynman teach-back and real spaced repetition that prove you actually learned it.
Knowt won a lot of students by keeping flashcards and study modes free. Synapsi is free to start, keeps review free, and goes one step further: it checks you understood the material, not just that you generated cards from it.
Use Knowt if you just want fast free flashcards. Use Synapsi if you want proof you actually learned them.
Prove you actually learned it.
Free to start, no card. A 3-day free trial unlocks everything.