backend

StellarSplit Backend

NestJS backend for StellarSplit - a crypto-powered bill splitting application.

🚀 Quick Start

Prerequisites

• Node.js 18+
• PostgreSQL 12+
• npm

Installation

1. Install dependencies:

   npm install

2. Configure environment variables:

   cp .env.example .env

   Edit .env with your database credentials and configuration.

3. Build the project:

   npm run build

4. Start the application:

   # Development with live reload
   npm run dev:watch
   
   # Or production build
   npm run start

The API will be available at http://localhost:3000

📚 API Documentation

Once the application is running, visit:

• Swagger UI: http://localhost:3000/api/docs
• OpenAPI JSON: http://localhost:3000/api-docs

📁 Project Structure

src/
├── main.ts                 # Application entry point
├── app.module.ts          # Root application module
├── config/                # Configuration modules
│   ├── app.config.ts      # Application configuration
│   └── database.config.ts # Database configuration
├── database/              # Database configuration and utilities
│   └── typeorm.config.ts  # TypeORM configuration
└── modules/               # Feature modules
    └── health/            # Health check module
        ├── health.controller.ts
        ├── health.service.ts
        └── health.module.ts

🔧 Configuration

Environment Variables

Create a .env file in the backend root directory:

# Server
NODE_ENV=development
PORT=3000

# Database
DB_HOST=localhost
DB_PORT=5432
DB_USERNAME=postgres
DB_PASSWORD=postgres
DB_NAME=stellarsplit_dev
DB_SYNCHRONIZE=true
DB_LOGGING=false

# Swagger
SWAGGER_PATH=/api/docs
SWAGGER_TITLE=StellarSplit API
SWAGGER_DESCRIPTION=API for StellarSplit - Split bills instantly with crypto
SWAGGER_VERSION=1.0.0

🏥 Health Check Endpoint

GET /health

Returns the API health status:

{
  "status": "ok",
  "timestamp": "2026-01-21T12:00:00.000Z",
  "uptime": 123.456
}

📦 Dependencies

Core

• @nestjs/core - NestJS core framework
• @nestjs/common - Common NestJS utilities
• reflect-metadata - Metadata reflection API
• rxjs - Reactive programming library

Database

• @nestjs/typeorm - TypeORM integration for NestJS
• typeorm - ORM for database management
• pg - PostgreSQL driver

Configuration

• @nestjs/config - Configuration management
• dotenv - Environment variable loading

Validation & Transformation

• class-validator - Data validation decorators
• class-transformer - DTO transformation

API Documentation

• @nestjs/swagger - Swagger/OpenAPI integration

Development

• typescript - TypeScript compiler
• ts-node - Execute TypeScript directly
• nodemon - Auto-reload on file changes

📋 Available Scripts

• npm run build - Build the project for production
• npm run start - Run the built application
• npm run dev - Run the application in development mode
• npm run dev:watch - Run with auto-reload on file changes
• npm test - Run tests (not yet configured)

🗄️ Database Setup

The application uses PostgreSQL with TypeORM. On first run with DB_SYNCHRONIZE=true, the database schema will be automatically created.

Connect to PostgreSQL

# If running PostgreSQL locally
psql -U postgres -d stellarsplit_dev

🚦 Acceptance Criteria Status

✅ NestJS project initialized
✅ TypeORM connected to PostgreSQL
✅ Environment variables loaded
✅ Health check endpoint returns 200
✅ Swagger API docs configured
✅ Backend starts without errors

🤝 Contributing

See CONTRIBUTING.md for development guidelines.

📝 License

See LICENSE for licensing information.