Anki is an intelligent flashcard system designed to help users quickly learn new information. Cards can contain nearly anything, including audio, video, images, text, and LaTeX formatted scientific markup. Anki schedules cards for review using the SuperMemo spaced repetition algorithm, which is based on academic research on learning and retention. The Anki website suggests a few sample uses, from learning new languages to practicing guitar chords. Roger Craig used Anki to prepare for his 2010 appearance on the quiz show Jeopardy! in which he set the record for highest single-day winnings. By using the AnkiWeb service, users can synchronize sets of flashcards and their learning statistics across all their devices. Anki can be downloaded for Windows, macOS, Linux, iPhone, and Android. Anki is distributed under the GNU Affero General Public License version 3, with source code available via GitHub.