How to Use Nginx with Express for Node.js Apps

To use nginx with an express app, configure nginx as a reverse proxy that forwards HTTP requests to your Express server running on a specific port. This setup improves performance, handles static files, and adds security by isolating your app from direct internet access.

Syntax

Here is the basic syntax to configure nginx as a reverse proxy for an express app:

• server: Defines the server block for your domain or IP.
• listen: The port nginx listens on (usually 80 for HTTP).
• location /: Matches all requests to forward.
• proxy_pass: The URL where nginx forwards requests (your Express app address).
• proxy_set_header: Passes headers like Host and X-Real-IP to Express for correct request info.

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_cache_bypass $http_upgrade;
        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;
    }
}

Example

This example shows a simple Express app running on port 3000 and an nginx config forwarding requests from port 80 to the app. It demonstrates how nginx acts as a middleman between users and your Express server.

javascript and nginx

// app.js - Express server
import express from 'express';
const app = express();
const PORT = 3000;

app.get('/', (req, res) => {
  res.send('Hello from Express behind Nginx!');
});

app.listen(PORT, () => {
  console.log(`Express server running on http://localhost:${PORT}`);
});


# nginx.conf snippet
server {
    listen 80;
    server_name localhost;

    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_cache_bypass $http_upgrade;
        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;
    }
}

Output

Express server running on http://localhost:3000

When accessing http://localhost in a browser, you see:
Hello from Express behind Nginx!

Common Pitfalls

Common mistakes when using nginx with express include:

• Not forwarding headers like Host and X-Real-IP, causing Express to get wrong client info.
• Forgetting to set proxy_http_version 1.1 and connection upgrade headers, which breaks WebSocket support.
• Running Express on the same port as nginx (usually 80), causing port conflicts.
• Not restarting nginx after config changes.

Example of a wrong config missing headers:

nginx

server {
    listen 80;
    server_name yourdomain.com;

    location / {
        proxy_pass http://localhost:3000;
        # Missing proxy_set_header lines
    }
}

# Corrected config includes:
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;

Quick Reference

Tips for using nginx with express:

• Run Express on a port like 3000, not 80.
• Use nginx to handle static files and SSL termination.
• Always forward important headers for correct client info.
• Reload nginx after config changes with sudo nginx -s reload.
• Test your setup locally before deploying.

Key Takeaways

Use nginx as a reverse proxy to forward requests to your Express app running on a separate port.

Always set proxy headers in nginx to pass client info correctly to Express.

Run Express on a non-privileged port like 3000 and let nginx listen on port 80 or 443.

Reload nginx after any configuration changes to apply them.

Use nginx to improve security, performance, and enable features like SSL termination.