Anki Spaced Repetition Software

Anki is a free and open-source flashcard application that uses spaced repetition algorithms to optimize learning and memorization. Created by Damien Elmes in 2006 and written in Python with Rust backend components, Anki has millions of users worldwide for language learning, medical school exam preparation, and professional certification study. Key features: spaced repetition using an optimized variant of the SuperMemo SM-2 algorithm for scheduling card reviews, automatically calculating review intervals based on card difficulty and user performance. Flexible card model with customizable note types, fields, and templates, allowing creation of basic, cloze deletion, image occlusion, and custom card types. Cloze deletions for fill-in-the-blank style cards where text is hidden and must be recalled. Embed images, audio, video, and LaTeX mathematical formulas in flashcards with automatic media syncing via AnkiWeb. Free cloud synchronization service for syncing card decks and review progress across multiple devices. AnkiDroid (free Android app) and AnkiMobile (paid iOS app) for reviewing flashcards on mobile with offline support. Over 1,000 community add-ons extending functionality including enhanced statistics and custom card types. Download and share pre-made card decks from shared library with millions of decks for languages, sciences, medicine, and law. Detailed review statistics including retention rates, forecast graphs, and review heatmaps. FSRS algorithm support as optional replacement for SM-2 with improved accuracy. Flexible tagging system for organizing and filtering cards. Cross-platform desktop applications plus mobile apps.