OpenRouter Express Starter

A production-ready Express.js API server for interacting with OpenRouter's LLM API.

Features

• ✅ Helmet middleware for security headers
• ✅ CORS origin restrictions in production
• ✅ Rate limiting on /api/chat endpoint
• ✅ Server timeouts configured
• ✅ Docker containerization support
• ✅ Environment-based configuration
• ✅ Health check endpoint

Prerequisites

• Node.js 20+ (or Docker)
• OpenRouter API key

Environment Variables

Copy env.example to .env and configure:

cp env.example .env

Required variables:

• OPENROUTER_API_KEY - Your OpenRouter API key
• ALLOWED_ORIGINS - Comma-separated list of allowed CORS origins (production only)
• NODE_ENV - Set to production for production deployment
• PORT - Server port (default: 3000)
• OPENROUTER_DEFAULT_MODEL - Default model to use (default: x-ai/grok-4.1-fast)

Local Development

# Install dependencies
npm install

# Run in development mode
npm run dev

# Build for production
npm run build

# Run production build
npm start

Docker Deployment

Using Docker Compose (Recommended)

# Build and start the container
docker-compose up -d

# View logs
docker-compose logs -f

# Stop the container
docker-compose down

Using Docker directly

# Build the image
docker build -t openrouter-express-starter .

# Run the container
docker run -d \
  --name openrouter-express-starter \
  -p 3000:3000 \
  --env-file .env \
  openrouter-express-starter

Production Deployment on VPS (AWS EC2, DigitalOcean, etc.)

Option 1: Docker Compose

1. SSH into your VPS

   ssh user@your-server-ip

2. Install Docker and Docker Compose

   # Ubuntu/Debian
   curl -fsSL https://get.docker.com -o get-docker.sh
   sh get-docker.sh
   sudo usermod -aG docker $USER
   
   # Install Docker Compose
   sudo curl -L "https://github.com/docker/compose/releases/latest/download/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
   sudo chmod +x /usr/local/bin/docker-compose

3. Clone your repository

   git clone https://github.com/Shriansh2002/openrouter-express-starter.git
   cd openrouter-express-starter

4. Create .env file

   cp env.example .env
   nano .env  # Edit with your values

5. Start the application

   docker-compose up -d

6. Set up reverse proxy (NGINX)

   server {
       listen 80;
       server_name yourdomain.com;
   
       location / {
           proxy_pass http://localhost:3000;
           proxy_http_version 1.1;
           proxy_set_header Upgrade $http_upgrade;
           proxy_set_header Connection 'upgrade';
           proxy_set_header Host $host;
           proxy_set_header X-Real-IP $remote_addr;
           proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
           proxy_set_header X-Forwarded-Proto $scheme;
           proxy_cache_bypass $http_upgrade;
   
           # Timeouts
           proxy_connect_timeout 30s;
           proxy_send_timeout 30s;
           proxy_read_timeout 30s;
       }
   }

Option 2: Direct Node.js Deployment

1. Install Node.js 20+

   curl -fsSL https://deb.nodesource.com/setup_20.x | sudo -E bash -
   sudo apt-get install -y nodejs

2. Clone and build

   git clone https://github.com/Shriansh2002/openrouter-express-starter.git
   cd openrouter-express-starter
   npm ci
   npm run build

3. Set up PM2 for process management

   npm install -g pm2
   pm2 start dist/server.js --name openrouter-express-starter
   pm2 save
   pm2 startup  # Follow instructions to enable auto-start

4. Configure environment variables

   cp env.example .env
   nano .env

Security Features

• Helmet: Sets various HTTP headers for security
• CORS: Restricted origins in production mode
• Rate Limiting: 50 requests per 15 minutes per IP (production)
• Timeouts: 30s request timeout, 65s keep-alive timeout
• Non-root user: Docker container runs as non-root user

API Endpoints

POST /api/chat

Send a chat request to the LLM.

Request Body:

{
	"messages": [
		{
			"role": "user",
			"content": "Hello, how are you?"
		}
	],
	"model": "x-ai/grok-4.1-fast", // optional
	"stream": false // optional, currently not supported
}

Response:

{
	"model": "x-ai/grok-4.1-fast",
	"message": {
		"role": "assistant",
		"content": "I'm doing well, thank you!"
	},
	"usage": {
		"prompt_tokens": 10,
		"completion_tokens": 8,
		"total_tokens": 18
	}
}

GET /health

Health check endpoint.

Response:

{
	"status": "ok"
}

Rate Limiting

• Production: 50 requests per 15 minutes per IP
• Development: 100 requests per 15 minutes per IP

Rate limit headers are included in responses:

• RateLimit-Limit: Maximum requests allowed
• RateLimit-Remaining: Remaining requests in current window
• RateLimit-Reset: Time when the rate limit resets

Monitoring

The application includes a health check endpoint at /health that can be used with monitoring tools or load balancers.

License

MIT