kana-dojo

KanaDojo drills Japanese in the browser, Duolingo style, with no account and no paywall. It covers hiragana and katakana, kanji from JLPT N5 up through N1, and vocabulary that goes just as deep, with streaks, achievements and about 35 experimental mini-games and toys to keep you coming back. It also ships a translator, a verb conjugator and an Anki deck converter. AGPL-3.0.

There's nothing to set up. kanadojo.com works out of the box. For your own copy there's a Dockerfile and a Vercel guide. The drills run in the browser, but the translator, progress sync and bug reports each need third-party keys (Google or Azure translation, Upstash Redis). Run a modified version publicly and the AGPL means you share your changes.

The hosted site is free and now carries Google ads, plus a Ko-fi donation prompt after streak milestones. Solo learners: use the hosted site. Teachers and schools: self-host to drop the ads. Review works by mixing learned sets back in based on how well you know them, not an Anki-style schedule with due dates.

The catch: it's recognition and recall practice only. No grammar course and no listening or speaking practice (it can read words aloud with your browser's text-to-speech), so pair it with a textbook or a tutor. And ignore the star count. The repo auto-posts thousands of no-code "good first issues" whose first step asks you to star the repo, so popularity here says nothing about quality.