How to set up Nginx as a reverse proxy

Modern apps (Node, Python, Java) run on an internal port, for example 3000. An Nginx reverse proxy receives traffic on port 80/443 and forwards it to the app, handling the domain and HTTPS.

Why you need a reverse proxy

• Serve on the standard 443 port with HTTPS, not on an odd port.
• Run multiple apps on one server, each with its own domain.
• Add caching, compression and rate limiting in one place.

Configuration

Assume the app runs on 127.0.0.1:3000. Create the server block:

server {
    listen 80;
    server_name app.example.com;

    location / {
        proxy_pass http://127.0.0.1:3000;
        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;
    }
}

nginx -t && systemctl reload nginx

Add HTTPS

Run Certbot for a free certificate; see Free SSL certificate with Let's Encrypt. To run the Node app as a service, see How to deploy a Node.js app.