Everything You Need to Learn

Powerful features designed for serious language learners — all completely free.

Core Engine

FSRS Spaced Repetition

The Ebbinghaus Forgetting Curve shows that without review, we forget ~50% of new information within hours. FluentCards counteracts this with the Free Spaced Repetition Scheduler (FSRS) — a modern algorithm that replaces the traditional SM-2 system. By reviewing cards at optimal moments, FSRS keeps your memory retention high with fewer reviews overall.

FSRS adapts to your memory by tracking three key metrics:

  • S Stability — How long the memory will last. FSRS increases stability for cards you recall easily.
  • D Difficulty — How hard the card is intrinsically. Difficult cards appear more often.
  • R Retrievability — The probability you'll remember the card today. Reviews trigger when it drops below target.

Ebbinghaus Forgetting Curve

How FSRS reviews counteract natural memory decay

0% 25% 50% 75% 100% 0 1 2 3 4 5 6 7 Days without review with FSRS reviews

Up to 2x fewer reviews

vs. traditional spaced repetition systems

漢字かんじ

Automatic Ruby Annotation Rendering

Japanese Learning

Smart Furigana Rendering

Type kanji with furigana using the simple 漢字[かんじ] syntax and FluentCards renders it beautifully with browser-native ruby annotations.

No complex markup or plugins needed. Works for Japanese, Chinese, and any other language with phonetic guides. You can also auto-generate furigana with a single click.

  • Simple bracket syntax: 語[ご]学[がく]
  • Auto-generate furigana with one tap
  • Clean, native browser rendering
  • Supports mixed kanji/kana text
Audio Learning

Native TTS Pronunciation

Hear how words are pronounced by native speakers using Microsoft Edge's neural TTS engine. Supports Japanese, Chinese, Korean, Spanish, French, German, and many more languages.

Adjust the speech rate to match your level, and toggle auto-play so cards read themselves when you flip them. Each language uses its region-specific voice for authentic pronunciation.

  • 20+ languages with neural voices
  • Adjustable speech rate (0.5x - 2.0x)
  • Auto-play on card flip
  • Manual playback with one tap

Microsoft Edge TTS

Neural text-to-speech with native voices

ja-JP ko-KR zh-CN es-ES fr-FR de-DE

AI-Generated Visual Memory Aids

Visual Memory Aids

AI Features

AI-Generated Mnemonics

Struggling with a difficult word? AI-powered image generation creates visual mnemonics to help you remember. Each mnemonic is a custom illustration tied to the meaning, making abstract concepts stick.

Toggle AI mnemonics per card — perfect for complex kanji, tricky vocabulary, or any concept that needs an extra memory hook.

Analytics

Review History & Stats

Track your learning journey with detailed FSRS metrics. See how your memory stability improves over time, which cards are最难 (most difficult), and your projected retention rate.

  • Stability and difficulty trends
  • Daily review counts
  • Retention rate estimates
  • Card-by-card progress

Shared Learning

Discover & Clone Decks

Marketplace

Community Marketplace

Browse public decks shared by the FluentCards community. From JLPT vocabulary to Spanish phrases, find ready-made decks and clone them to your library instantly.

Share your own curated decks with the community. Your knowledge helps others learn.

Ready to try these features?

All features are free. No subscriptions, no trials, no hidden charges.

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