Node.js Application Deployment

Learn how to prepare a Node.js application for production, configure environment variables, start a server, and deploy your application to a hosting platform.

1. What Is Deployment?

Deployment is the process of making an application available for users to access. During development, you usually run your application on your own computer. After deployment, users can access it through a public URL or domain.

http://localhost:3000

https://your-domain.com

2. What Do You Need for Deployment?

• A working Node.js application.
• A supported Node.js version.
• A hosting platform or server.
• A start command for your application.
• Environment variables for configuration and secrets.
• A database service, if your application needs one.
• Logs and error handling for troubleshooting.

3. Prepare a Node.js Project

For this lesson, create a simple Express application.

Step 1: Create the Project

mkdir node-deployment-demo
cd node-deployment-demo
npm init -y

Step 2: Install Express

npm install express

Step 3: Create server.js

const express = require('express');

const app = express();

const PORT = process.env.PORT || 3000;

app.get('/', (req, res) => {
    res.send('Welcome to Soopro Pathshala!');
});

app.get('/about', (req, res) => {
    res.json({
        application: 'Node.js Deployment Demo',
        message: 'Application is running successfully'
    });
});

app.get('/health', (req, res) => {
    res.status(200).json({
        status: 'ok'
    });
});

app.listen(PORT, '0.0.0.0', () => {
    console.log(`Server is running on port ${PORT}`);
});

4. Configure package.json

The hosting platform needs to know how to start your application. Add a start script to the scripts section of package.json.

{
    "name": "node-deployment-demo",
    "version": "1.0.0",
    "description": "Node.js deployment example",
    "main": "server.js",
    "scripts": {
        "start": "node server.js"
    },
    "dependencies": {
        "express": "^5.0.0"
    }
}

5. Test the Application Locally

Run the application using the start command.

npm start

Open these URLs in your browser:

• http://localhost:3000/
• http://localhost:3000/about
• http://localhost:3000/health

Expected Output

For the home page:

Welcome to Soopro Pathshala!

For the health endpoint:

{
    "status": "ok"
}

6. Development vs Production

7. Use Environment Variables

Production applications should receive their configuration from the hosting environment. Avoid hardcoding database passwords, API keys, and JWT secrets.

const PORT = process.env.PORT || 3000;
const NODE_ENV = process.env.NODE_ENV || 'development';

console.log(`Environment: ${NODE_ENV}`);

On your hosting platform, configure the required environment variables through its settings or secret-management system.

8. Deploy to a Hosting Platform

Many Node.js hosting providers let you connect a Git repository, install dependencies, and run a start command. The exact interface varies by provider.

Example Hosting Configuration

These are common settings, not a guarantee that every hosting provider uses the same configuration.

9. Deploy Using a VPS

A virtual private server (VPS) gives you more control over the server. You are generally responsible for installing Node.js, configuring the application process, securing the server, and setting up HTTPS.

Typical VPS Workflow

1. Provision a Linux server.
2. Install a supported Node.js version.
3. Upload or clone the application code.
4. Install production dependencies.
5. Configure environment variables securely.
6. Start the application with a process manager or service manager.
7. Configure a reverse proxy and HTTPS.
8. Set up logs, monitoring, and backups as needed.

Install Production Dependencies

npm ci --omit=dev

Run this command in the application directory when a compatible package-lock.json file is available. It installs the locked production dependencies without development dependencies.

10. What Is a Process Manager?

A process manager can keep an application running and help restart it after a crash or server reboot, depending on its configuration. PM2 is one commonly used Node.js process manager.

Install PM2

npm install -g pm2

Start the Application

pm2 start server.js --name node-demo

View Running Applications

pm2 list

View Logs

pm2 logs node-demo

Restart the Application

pm2 restart node-demo

PM2 is an optional tool. Many managed hosting platforms already handle application processes for you.

11. Deployment Security Checklist

12. Common Deployment Errors

13. Practical Assignment

14. Summary

• Deployment makes an application available to users.
• Test the application locally before deploying.
• Use npm start to run the configured start script.
• Use process.env.PORT for the hosting platform's port.
• Configure production secrets securely.
• Use logs to diagnose deployment problems.
• Protect the production application with appropriate security measures.