Flashcard apps have exploded in variety over the last few years. Choosing the wrong one can mean months of wasted effort migrating later, or worse — abandoning a study habit because the tool got in the way.
This is an honest comparison of the four most serious options in 2025: Anki, Quizlet, Flevro, and RemNote. We're the team behind Flevro, so we'll be transparent about where we fall short.
Quick Summary
| Anki | Quizlet | Flevro | RemNote | |
|---|---|---|---|---|
| Algorithm | SM-2 | None (simple) | FSRS-5 | FSRS variant |
| Price | Free + $24.99 iOS | Free + $35.99/yr | Free + $2.99/mo | Free + $8/mo |
| AI features | Via plugins | AI generation | Built-in | Note-based AI |
| Cloud sync | Via AnkiWeb | Native | Native | Native |
| Mobile app | Separate ($24.99) | Free | Free | Free |
| Best for | Power users | Casual learners | Serious learners | Note-takers |
Anki
Best for: Power users who want maximum control
Anki is the original serious flashcard app. Released in 2006, it's free on every platform except iOS ($24.99 one-time). Its plugin ecosystem is enormous — you can find community decks for almost any subject, including professionally maintained medical decks (like Anking for USMLE).
Strengths:
- Massive community deck library (AnkiWeb hosts millions of decks)
- Deeply customizable card templates (HTML/CSS)
- Free on desktop and Android
- Open-source; data is yours forever
Weaknesses:
- Interface is notoriously dated and non-intuitive
- SM-2 algorithm is 30+ years old and less efficient than modern alternatives
- iOS app costs $24.99 (though it funds development)
- Sync is through AnkiWeb, which can be unreliable
- No built-in AI tools; plugins are fragile
Quizlet
Best for: Students who want social features and pre-made sets
Quizlet is the most popular flashcard platform by user count, largely because of its massive library of student-created study sets and its use in K-12 and college classrooms.
Strengths:
- Enormous pre-made set library (hundreds of millions of sets)
- Social features: share sets, study with classmates
- AI-powered set generation (Quizlet Plus)
- Good-looking mobile apps
- Teacher-friendly features
Weaknesses:
- No real spaced repetition algorithm — scheduling is not science-backed
- Quality of community sets varies wildly
- Premium plan ($35.99/year) required for most useful features
- Optimized for short-term test prep, not long-term retention
Flevro
Best for: Serious learners who want modern tools without complexity
Flevro is built around FSRS-5, the most accurate spaced repetition algorithm available. The goal was to take what makes Anki work (rigorous algorithm, serious learner workflow) and pair it with a modern UX and built-in AI tools.
Strengths:
- FSRS-5 algorithm (~20% fewer reviews vs Anki for same retention)
- Built-in AI: card generation from text/URL/image, TTS in 30+ languages, translation, image generation
- Real-time cloud sync across web and mobile
- Anki import (.apkg, .colpkg) for easy migration
- Modern, clean interface with dark mode
- Free tier includes unlimited cards, 3 decks, full FSRS scheduling
Weaknesses:
- No community deck library yet (you need to build or import your own decks)
- Closed source (if open-source matters to you, Anki wins)
- Newer app — less battle-tested than Anki
RemNote
Best for: Note-takers who want spaced repetition integrated into their notes
RemNote is a knowledge management tool that also happens to have flashcards. If you take extensive notes and want to automatically generate flashcards from them, it's worth evaluating.
Strengths:
- Tight integration between notes and flashcards
- FSRS-based scheduling (recent update)
- PDF annotation with card creation
- Good for academic note-taking workflows
Weaknesses:
- More complex than dedicated flashcard apps
- $8/month for useful features
- Can feel overwhelming if you just want flashcards
Which Should You Choose?
- Choose Anki if you need community decks (especially USMLE/medical), want full offline functionality with no account, or prefer open-source tools
- Choose Quizlet if you're a student whose class already uses it, or you want to browse and fork existing sets
- Choose Flevro if you want the best algorithm, AI card creation, and a modern experience — and don't need an existing deck library
- Choose RemNote if your primary workflow is note-taking and you want flashcards as a byproduct of your notes
The Bottom Line on Algorithms
If long-term retention is your goal — language acquisition, professional certification, medical school — the algorithm matters more than the interface. FSRS-5 is the current state of the art. Read our full explanation of why.
Try Flevro free — no credit card required. If it's not the right fit, your Anki decks can be exported and you lose nothing.