Anki

Anki is a free and open-source flashcard program. It uses techniques from cognitive science such as active recall testing and spaced repetition to aid the user in memorization. The name comes from the Japanese word for "memorization" (暗記, anki; Japanese: [aŋʲ.kʲi]). The SM-2 algorithm, created for SuperMemo in the late 1980s, has historically formed the basis of the spaced repetition methods employed in the program. Anki's implementation of the algorithm has been modified to allow priorities on cards and to show flashcards in order of their urgency. Anki 23.10+ also has a native implementation of the Free Spaced Repetition Scheduler (FSRS) algorithm, which allows for more optimal spacing of card repetitions. Anki is content-agnostic, and the cards are presented using HTML and may include text, images, sounds, videos, and LaTeX equations. The decks of cards, along with the user's statistics, are stored in the open SQLite format.