This is a real-time chat API built with NestJS, TypeORM, and PostgreSQL (running in Docker). It provides:

• User registration & authentication (JWT-based)
• Chat messaging between users
• Database persistence with PostgreSQL
• Dockerized setup for easy local development
• Ready to scale for real-time features or microservices integration

• Backend: NestJS, TypeScript, TypeORM
• Database: PostgreSQL (Dockerized)
• Authentication: JWT
• Dev Tools: Docker Compose, npm

• User management (register, login)
• CRUD operations for chat messages
• Modular and clean architecture
• Easily extensible for future real-time updates (WebSockets)

src ├── auth │ ├── dto │ │ └── login.dto.ts │ ├── auth.controller.ts │ ├── auth.module.ts │ ├── auth.service.ts │ ├── jwt-auth.guard.ts │ └── jwt.strategy.ts ├── chat │ ├── dto │ │ ├── create-room.dto.ts │ │ └── send-message.dto.ts │ ├── entities │ │ ├── message.entity.ts │ │ └── room.entity.ts │ ├── chat.controller.ts │ ├── chat.gateway.ts │ ├── chat.module.ts │ └── chat.service.ts ├── users │ ├── dto │ │ └── create-user.dto.ts │ ├── entities │ │ └── user.entity.ts │ ├── users.controller.ts │ ├── users.module.ts │ └── users.service.ts ├── app.controller.spec.ts ├── app.controller.ts ├── app.module.ts ├── app.service.ts └── main.ts 

🛠 Setup & Run

1. Clone the repository

git clone https://github.com/Vintanina/chat-api.git

cd chat-api

2. Create .env file

DATABASE_URL=postgres://chat:chat@localhost:6543/chat_db PORT=3000 JWT_SECRET=your_jwt_secret

Adjust DATABASE_URL if Postgres is running in Docker with a different port or credentials. 

3. Start PostgreSQL with Docker (Optionnal)

docker compose up -d

The container exposes Postgres on port 6543. Check logs if needed: 

docker compose logs -f db

4. Install dependencies

npm install

5. Run the NestJS application

npm run start:dev

The API runs on http://localhost:3000 

6. Test the API

Example: register a user via curl:

curl -X POST http://localhost:3000/auth/register
-H "Content-Type: application/json"
-d '{"username":"alice","email":"alice@mail.com","password":"secret123"}'

7. Notes

   Make sure TypeOrmModule is properly configured with your entities and autoLoadEntities: true.

   If the database is slow to start, NestJS retries automatically (configured via retryAttempts and retryDelay).

   Use docker compose down -v to clean volumes if you want a fresh database.