Deploying Express.js Applications on Heroku: A Comprehensive Guide

Deploying your Express.js application can feel daunting at first, but Heroku makes the process surprisingly straightforward. In this guide, I’ll walk you through deploying your Node.js and Express application on Heroku, from setup to going live.

Prerequisites

Before we dive in, ensure you have:

• A working Express.js application
• Git installed on your machine
• A Heroku account
• Heroku CLI installed locally

Preparing Your Application

First, your Express.js application needs some adjustments for Heroku deployment:

1. Update your port configuration:

const port = process.env.PORT || 3000;
app.listen(port, () => {
    console.log(`Server running on port ${port}`);
});

2. Create a Procfile:

web: node app.js

3. Ensure your package.json includes:

{
  "scripts": {
    "start": "node app.js"
  },
  "engines": {
    "node": "14.x"
  }
}

Deployment Steps

1. Initialize Git (if haven’t already):

git init
git add .
git commit -m "Initial commit"

2. Login to Heroku CLI:

heroku login

3. Create Heroku app:

heroku create your-app-name

4. Deploy your application:

git push heroku main

Post-Deployment

After deployment, verify your application:

• Check logs: heroku logs --tail
• Open app: heroku open
• Monitor dashboard through Heroku’s web interface

Common Issues and Solutions

1. Application Crashes

• Check logs immediately
• Verify environment variables
• Ensure all dependencies are in package.json

2. Port Binding Errors

• Double-check port configuration
• Ensure you’re using process.env.PORT

3. Module Not Found Errors

• Verify all dependencies are in package.json
• Run npm install locally first
• Check node_modules is in .gitignore

Remember to regularly monitor your application’s performance and logs through Heroku’s dashboard. Happy deploying!