Flashcards with spaced repetition — the Android companion to Anki, synced with AnkiWeb free of charge.
Study tool with local card storage. Network use is limited to optional AnkiWeb sync you configure; no ads or trackers.
AnkiDroid is a flashcard app built around spaced repetition: cards you find hard come back sooner, cards you know well come back later. Scheduling, deck stats, and filtered decks follow the Anki ecosystem, so existing Anki users can sync decks through the free AnkiWeb service and keep studying on the move. Cards support images, audio, math (via LaTeX rendering), and cloze deletions. The in-app card browser, note editor, and statistics graphs match desktop Anki workflows closely. Deck files are standard .apkg and can also be transferred directly. AnkiDroid is entirely volunteer-built, open source, and free — no in-app purchases, no ads, no premium tier.
AnkiDroid by AnkiDroid Open Source Project — Education app, 20 MB, requires Android 6.0+. Direct APK download on AppsDone, scanned for malware.