Deck Lens vs Lumen

Study smarter, not harder. Deck Lens is a clean, focused flashcard app built for learners who love Anki but want a more modern experience on their phone. Import your existing Anki decks, study with proven spaced repetition, and watch your progress grow — all without the clutter. Import Your Anki Decks Instantly Already have .apkg files? Just open them in Deck Lens. Your cards, media, and deck structure come along for the ride. Switching from Anki has never been easier. Spaced Repetition That Works Deck Lens uses the SM-2 algorithm — the same proven system behind Anki — to schedule your reviews at the perfect time. Rate each card as Again, Hard, Good, or Easy, and the app handles the rest. You'll see exactly when each card comes back before you tap. A Study Experience You'll Actually Enjoy Flip through cards with smooth animations, track your session progress, and get a summary when you're done. Set daily review limits so you never feel overwhelmed. Swipe Mode Prefer gestures? Swipe through your cards for a fast, tactile study flow. Know Where You Stand Check your stats anytime: review heatmap, retention rate, streak counter, and cards broken down by status (new, learning, review). See what's working and where to focus. Create and Edit Your Own Decks Build flashcards from scratch or tweak imported ones. Deck Lens supports rich card content so your notes look the way you want. Export and Share Export any deck back to .apkg format and share it with friends, classmates, or your other devices. Your data is always yours. Available in English, German, and Turkish. Whether you're learning a new language, studying for exams, or memorizing anything else — Deck Lens gives you the tools to make it stick.

Lumen is a flashcard app for people who want spaced repetition to work properly and want their data to stay on their phone. Cards are scheduled with FSRS-6, the algorithm that models memory as difficulty, stability, and retrievability rather than a fixed ladder of intervals. Every rating button shows the interval it would give you before you tap it, so you can see what Again, Hard, Good, and Easy actually cost. If you want to tune the scheduler, all 21 FSRS weights and your desired retention are editable, with bounds checking so you cannot save a set that breaks scheduling. BRING THE DECKS YOU ALREADY HAVE Import from Anki .apkg files, Anki JSON, CSV and TSV, Markdown, and Lumen's own ZIP backups. Anki's rendered HTML is stripped on the way in, so you get clean card faces instead of stray markup. Imports are idempotent: re-importing a deck or overlapping HSK levels will not duplicate anything. You can export your decks at any time. BUILT FOR CHINESE, USEFUL FOR EVERYTHING The HSK importer reads the complete-hsk-vocabulary dataset and keeps every written form, numeric pinyin, radical, and frequency rank. Chinese notes render tone-colored pinyin alongside simplified and traditional forms, meanings, part of speech, HSK level, and classifiers. Each word can generate both recognition and production cards. Text-to-speech reads cards aloud, and the spoken language is set per deck. For everything else there are Basic, Basic and Reversed, and Cloze note types, Markdown formatting on card faces, nested decks at any depth, image and audio attachments, and full-text search across your collection. YOUR CARDS STAY ON YOUR DEVICE Lumen works offline and has no accounts. Your decks, notes, review history, and media live in a database on your phone, and nothing syncs to a server. Lumen reports anonymous usage and crash data so bugs get fixed, and that reporting excludes deck names, tag names, note contents, search queries, and file paths. Settings has a reset that erases everything locally. KEEPING THE HABIT A daily goal, streaks, XP, and achievements track consistency. The stats screen shows review counts, retention, daily accuracy, rating distribution, how card difficulty is trending, and a heatmap of your study activity. You can share a streak or heatmap card as an image without sharing the cards themselves. Lumen has no ads and nothing to unlock by paying.