kana-dojo

Kana Dojo is a minimalist Japanese language learning app inspired by Duolingo, built with Next.js. Covers hiragana, katakana, and vocabulary with spaced repetition. Clean UI, gamified progress tracking, and a focus on the fundamentals that trip up beginners.

Fully free, no ads, no paid tier. Sponsored by Vercel. The codebase is beginner-friendly with labeled good-first-issues, so it doubles as a learning project for Next.js developers.

The catch: Japanese only. No other languages supported, and the curriculum covers kana and basic vocabulary, not grammar or conversation. If you're past the beginner stage, you'll outgrow it quickly. For comprehensive Japanese learning, Anki with community decks goes much deeper.