It uses techniques from cognitive science such as active recall testing and spaced repetition to aid the user in memorization.

[6] 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.

[7] Anki is content-agnostic, and the cards are presented using HTML and may include text, images, sounds, videos,[8] and LaTeX equations.

There also is a third-party open-source (AGPLv3) AnkiWeb alternative, called anki-sync-server,[10] which users can run on their own local computers or servers.

[13] They provide support for speech synthesis, enhanced user statistics, image occlusion, incremental reading, more efficient editing and creation of cards through batch editing, modifying the GUI, simplifying import of flashcards from other digital sources, adding an element of gamification,[14] etc.

[7] At the time, this led Elmes to claim that SM-5 and later algorithms were flawed[17] which was strongly rebutted by Piotr Woźniak, the author of SuperMemo.

[22] FSRS is based on a variant of the DSR (Difficulty, Stability, Retrievability) model, which is used to predict memory states.

[23][24] The following smartphone/tablet and Web clients are available as companions to the desktop version:[25][26][27] The flashcards and learning progress can be synchronized both ways with Anki using AnkiWeb.

[42] In the same year, another study showed that students had a one-point increase on their licensing exams for every 1,700 unique Anki flashcards they used.

[45] Anki offers user-made decks, which are commonly used in medical education and for learning a range of subjects including Chemistry, Biology, Geography, History, Law, Mathematics, Music, and Physics.

User-made decks are also available for learning languages such as Arabic, Chinese, English, French, German, Hebrew, Japanese, Korean, Russian, and Spanish.