Hanyu — Personal Mandarin Learning PWA

A single-user Mandarin Chinese learning app: AI journal feedback, graded story reader, spaced-repetition flashcards, streaming AI chat with Harry Potter personas, and an AI-assessed HSK progress dashboard.

Stack

• Frontend: React 18 + Vite + Tailwind (PWA) → Vercel
• Backend: Node 24 + Express + WebSocket (ws) → Railway
• Database/Auth: Supabase (Postgres + Auth)
• Cache: Upstash Redis (REST)
• AI: Anthropic Claude (Sonnet 4.6 + Haiku 4.5)

Local development

npm install
cd client && npm install && cd ..
cd server && npm install && cd ..

# copy and fill in env files
cp server/.env.example server/.env
cp client/.env.example client/.env

npm run dev   # client on :5173, server on :3001

Docs

• docs/PRD.md — product spec
• docs/SETUP.md — full environment + deployment guide
• docs/SCHEMA.md — database schema (see supabase/migrations/)
• docs/PROMPTS.md — all Claude prompt templates
• docs/DESIGN.md — UI/UX spec
• CLAUDE.md — engineering rules for this codebase