Train your thinking for technical interviews by recording and reviewing your problem-solving explanations.
Rewind is a spaced-repetition learning system designed for DSA interview preparation. Instead of just solving problems, you record audio explanations of your approach, then revisit them periodically to reinforce your understanding.
Core Philosophy: Interview success comes from how you think, not just what you know.
┌─────────────────────────────────────────────────────────────────┐
│ Frontend (React PWA) │
│ ┌─────────┐ ┌──────────┐ ┌─────────┐ ┌─────────┐ ┌───────────┐ │
│ │ Login │ │Dashboard │ │Questions│ │ Solve │ │ Revisions │ │
│ └────┬────┘ └────┬─────┘ └────┬────┘ └────┬────┘ └─────┬─────┘ │
│ │ │ │ │ │ │
│ └───────────┴────────────┴───────────┴────────────┘ │
│ │ │
│ ┌─────────▼─────────┐ │
│ │ API Client │ │
│ │ + Audio Recorder │ │
│ └─────────┬─────────┘ │
└──────────────────────────────┼──────────────────────────────────┘
│ REST API + JWT
┌──────────────────────────────▼─────────────────────────────────-─┐
│ Backend (Spring Boot) │
│ ┌──────────────────────────────────────────────────────────────┐│
│ │ Security (JWT + Supabase) |│
│ └──────────────────────────────────────────────────────────────┘│
│ ┌────────────┐ ┌────────────┐ ┌────────────┐ ┌────────────────┐ │
│ │ Questions │ │ Solutions │ │ Recordings │ │ Revisions │ │
│ │ Controller │ │ Controller │ │ Controller │ │ Controller │ │
│ └─────┬──────┘ └─────┬──────┘ └─────┬──────┘ └───────┬────────┘ │
│ │ │ │ │ │
│ ┌─────▼──────────────▼──────────────▼────────────────▼────────┐ │
│ │ JPA Repositories │ │
│ └─────────────────────────┬───────────────────────────────────┘ │
└────────────────────────────┼─────────────────────────────────────┘
│
┌────────────────────────────▼─────────────────────────────────────┐
│ Supabase (PostgreSQL) │
│ ┌─────────┐ ┌─────────┐ ┌──────────────┐ ┌───────────────────┐ │
│ │ Users │ │Questions│ │ Recordings │ │ Revision Schedule │ │
│ │ │ │ Patterns│ │ Solutions │ │ Readiness Stats │ │
│ └─────────┘ └─────────┘ └──────────────┘ └───────────────────┘ │
└──────────────────────────────────────────────────────────────────┘
| Layer | Technology |
|---|---|
| Frontend | React 19, TypeScript, Vite 7, TanStack Query |
| Auth | Supabase Auth (Email/Password) |
| Backend | Spring Boot 3.2, Java 17, Lombok |
| Database | PostgreSQL (Supabase) |
| Migrations | Flyway |
| State | Zustand |
| PWA | Vite PWA Plugin, Workbox |
rewind/
├── rewind-backend/ # Spring Boot API
│ ├── src/main/java/com/rewind/
│ │ ├── controller/ # 6 REST controllers
│ │ ├── model/ # 13 JPA entities
│ │ ├── repository/ # Data access layer
│ │ ├── service/ # Business logic
│ │ └── config/ # Security, JWT
│ └── src/main/resources/
│ └── db/migration/ # Flyway SQL migrations
│
└── rewind-frontend/ # React PWA
└── src/
├── api/ # API client
├── lib/ # Supabase config
├── pages/ # 5 page components
├── stores/ # Zustand auth store
└── hooks/ # Audio recorder hook
- Java 17+
- Node.js 18+
- Supabase account
cd rewind-backend
export JAVA_HOME=/path/to/java17
cp .env.example .env # Add your Supabase credentials
source .env
mvn spring-boot:runcd rewind-frontend
cp .env.example .env # Add Supabase URL and anon key
npm install
npm run devCore Entities:
User- Auth profile synced with SupabasePattern- 21 DSA patterns (Two Pointers, Sliding Window, etc.)Question- 169 curated LeetCode problemsUserQuestion- User's progress on each questionSolution- Submitted code with languageExplanationRecording- Audio recordings with transcriptRevisionSchedule- Spaced repetition queueReadinessSnapshot- Interview readiness tracking
| Feature | Description |
|---|---|
| Curated Question Bank | 169 must-do DSA problems organized by pattern |
| Audio Recording | Record your thought process while solving |
| Spaced Repetition | Smart revision scheduling based on confidence |
| Readiness Meter | "Days to MAANG readiness" tracker |
| Pattern Filtering | Filter questions by pattern + difficulty |
| PWA Support | Install as app, works offline |
- AI Feedback - Gemini integration for analyzing explanations
- Transcript Generation - Auto-transcribe recordings with Whisper
- Progress Analytics - Charts showing improvement over time
- Share Recordings - Share explanations with study groups
- Study Groups - Create/join groups for accountability
- Leaderboards - Compete with friends on consistency
- Discussion Threads - Discuss approaches per question
- Mock Interviews - Pair up for practice sessions
- Company-specific Tracks - Google, Meta, Amazon question sets
- Behavioral Questions - STAR method recorder
- Mobile App - Native iOS/Android with React Native
- Browser Extension - Record directly on LeetCode
- Fork the repository
- Create your feature branch (
git checkout -b feature/amazing-feature) - Commit your changes (
git commit -m 'Add amazing feature') - Push to the branch (
git push origin feature/amazing-feature) - Open a Pull Request
MIT License - see LICENSE for details.
Built with ❤️ by Gajanan