Langora

Learn Chinese the way you learn touch‑typing. Read an English prompt, hear the audio, type the pinyin — get instant, gamified feedback.

中文文档 · [Report a bug](GitHub Repository/issues) · [Request a feature](GitHub Repository/issues)

Overview

Langora is an interactive practice app for Chinese learners, inspired by TypingClub's "type‑to‑progress" model. Each question shows an English prompt and auto‑plays its audio; the learner types the matching pinyin, and the app validates the answer, plays sound effects, and records progress in real time.

Lessons are grouped by theme — Greetings, Casual Conversation, Ordering Food, and more — and the content is monetized through a monthly subscription, a lifetime plan, and single‑lesson purchases.

🔗 Live demo: [https://langora.joy-codex.com] · 📦 Repository: [GitHub Repository](https://github.com/KapiYue/Langora)

Screenshots

Course Store — browse lessons by topic and access tier	Dashboard — streaks, accuracy, and recent lessons
Simple, transparent pricing — Free, Monthly Pro, and Lifetime

Features

Learning experience

• Type‑to‑progress drills — English prompt + auto‑played audio; answer in pinyin with lenient matching (case, tone numbers, and extra spaces are ignored), and multiple accepted answers per question.
• Immersive feedback — keystroke, correct, and error sound effects, plus a confetti animation on lesson completion.
• Keyboard shortcuts — Ctrl + P replays the audio, Enter submits an answer or advances to the next question.
• Progress visualization — per‑item progress bar, question counter, and live accuracy tracking.

Authentication

• Email/password sign‑up, login, forgot‑password, and reset flows powered by Supabase Auth.
• Cookie‑based SSR sessions (@supabase/ssr), refreshed centrally through Next.js Middleware.

Dashboard

• Learning overview: lessons completed, total words mastered, current streak, weekly practice time, and average accuracy.
• Recent lessons, a course store with per‑lesson progress, a profile page, and account settings (password change).

Content & access control

• Lessons, lesson items, and progress are stored in Postgres and can be imported via a seed script.
• Access rules: the free lesson (greetings_l1) is open to everyone; Pro and Lifetime members unlock every lesson; single‑lesson purchases unlock just that lesson.

Payments & membership (Creem)

• Three tiers: Free, Monthly Pro ($10/mo), Lifetime ($99 one‑time) — plus standalone single‑lesson purchases.
• Webhook requests are verified with an HMAC‑SHA256 signature check (crypto.timingSafeEqual) before any data is written.
• Grace period on cancellation — a canceled subscription stays active until the end of the current billing cycle; a refund revokes access immediately.
• Upgrade protection — purchasing Lifetime access automatically cancels an active Monthly Pro subscription to prevent double billing.
• Duplicate‑purchase guard — blocks redundant checkouts when the user already owns an equal or higher tier.

Tech stack

Area	Technology
Framework	Next.js 15 (App Router, Turbopack), React 19
Language	TypeScript 5
UI	Tailwind CSS 3, shadcn/ui (Radix UI), Framer Motion, lucide-react
Auth	Supabase Auth (@supabase/ssr, cookie/SSR)
Database	Supabase Postgres + Drizzle ORM (postgres-js driver)
Migrations	drizzle-kit
Payments	Creem (Checkout + Webhook)
Misc	use-sound, react-confetti, next-themes

Architecture

flowchart LR
  U[Browser] -->|SSR / Client| N[Next.js App Router]
  N -->|Middleware session refresh| SB[(Supabase Auth)]
  N -->|Drizzle ORM| PG[(Supabase Postgres)]
  N -->|Create checkout| CR[Creem API]
  CR -->|Webhook event + signature| N
  N -->|Write subscriptions / purchases / transactions| PG

Loading

Data model

Table	Purpose
lessons	Lessons (title, description, tag, order, cover image)
lesson_items	Lesson items (English prompt, Chinese, pinyin, accepted answers, audio)
user_profiles	Profile and aggregate stats (lessons completed, words mastered, streak)
user_lesson_progress	Lesson‑level progress (completed items, accuracy, time spent)
user_item_progress	Item‑level progress (attempts, correct attempts)
user_daily_stats	Daily learning statistics
user_subscriptions	Pro / Lifetime subscriptions
user_course_purchases	Single‑lesson purchases
payment_transactions	Payment transaction ledger

Project structure

app/
  page.tsx                 # Landing page (Hero / Features / Pricing / ...)
  auth/                     # Login / sign-up / password recovery
  dashboard/                # Overview / courses / membership / billing / profile / settings
  lesson/[lessonId]/        # Lesson player (with access control)
  api/
    lesson-progress/        # Save learning progress
    payment/                # checkout / webhook / status / cancel
components/                 # Landing page, dashboard, lesson, and shared UI components
lib/
  supabase/                 # client / server / middleware
  db/                       # schema / queries / seed / connection
  creem.ts                  # Payment config and helpers
  membership/plans.ts       # Plan definitions
drizzle/                    # Migration files
docs/                       # API references, lesson seed data, screenshots

Getting started

Prerequisites

• Node.js ≥ 20 and pnpm
• A Supabase project (Postgres + Auth)
• A Creem account (the test environment is fine)

1. Install dependencies

pnpm install

2. Configure environment variables

Copy .env.example to .env.local and fill in the values:

# Supabase
NEXT_PUBLIC_SUPABASE_URL=
NEXT_PUBLIC_SUPABASE_PUBLISHABLE_OR_ANON_KEY=
DATABASE_URL=

# Site
NEXT_PUBLIC_SITE_URL=http://localhost:3000

# Creem
CREEM_API_KEY=
CREEM_WEBHOOK_SECRET=
NEXT_PUBLIC_CREEM_URL=https://test-api.creem.io
CREEM_LIFETIME_PRODUCT_ID=
CREEM_SUBSCRIPTION_PRODUCT_ID=
CREEM_SINGLE_COURSE_PRODUCT_ID=

3. Initialize the database

pnpm db:push     # sync the schema (or db:migrate to apply migrations)
pnpm db:seed     # import lessons from docs/lessons.json

4. Run the dev server

pnpm dev

Open http://localhost:3000.

Available scripts

Command	Description
pnpm dev	Start the dev server (Turbopack)
pnpm build / pnpm start	Build / run in production
pnpm lint	Run ESLint
pnpm db:generate	Generate a new migration
pnpm db:migrate / pnpm db:push	Apply migrations / push schema directly
pnpm db:studio	Open Drizzle Studio
pnpm db:seed	Seed lesson data from docs/lessons.json

Payments notes (Creem)

• Checkout sessions pass userId, paymentType, and lessonId through metadata, which the webhook uses to post ledger entries accurately.
• The webhook path (/api/payment/webhook) is excluded from the Middleware matcher so the session‑refresh logic never interferes with it, and it verifies its own signature independently.
• Switch between test and production by changing NEXT_PUBLIC_CREEM_URL and the three *_PRODUCT_ID environment variables.

Deployment

Recommended stack: Vercel + Supabase.

1. Create a Supabase project, then run migrations and seed the lesson data.
2. Set the environment variables above in your Vercel project (NEXT_PUBLIC_SITE_URL should point to your live domain).
3. Point the Creem webhook to https://<your-domain>/api/payment/webhook.

Roadmap

• More lesson themes and difficulty tiers
• Mistake review / spaced repetition
• Leaderboards and achievements
• Mobile UX polish
• Full UI internationalization (i18n)

Contributing

Contributions, issues, and feature requests are welcome. Please read CONTRIBUTING.md before opening a pull request, and note that this project follows a Code of Conduct.

Security

If you discover a security vulnerability, please follow the responsible‑disclosure process described in SECURITY.md instead of opening a public issue.

License

Released under the MIT License.