Deploying an application to Heroku is a straightforward process. Below is a step-by-step guide for deploying a web application to Heroku, whether it’s built with Node.js, Python, PHP, Ruby, Java, or another framework.

1. Prerequisites

Before deploying to Heroku, ensure you have:

• ✔ A Heroku account (Sign up here)
• ✔ Heroku CLI installed (Download here)
• ✔ Git installed (Check with git --version)
• ✔ A project directory with a Git repository (git init if needed)
• ✔ A Procfile (Defines how to run your app on Heroku)

2. Install and Login to Heroku CLI

After installing Heroku CLI, log in:

heroku login

This opens a browser for authentication. Once logged in, you can manage your Heroku apps from the command line.

3. Prepare Your Application

(i) Ensure Your App Has a Procfile

A Procfile tells Heroku how to run your app. Create one in the root directory:

For a Node.js app, add:

web: node server.js

For a Python app (Flask/Django):

web: gunicorn app:app

For a React app (Using serve):

web: serve -s build

For other frameworks, adjust accordingly.

(ii) Add a package.json or Requirements File

For Node.js, ensure your package.json includes:

"scripts": {
  "start": "node server.js"
}

For Python, include a requirements.txt with:

Flask
gunicorn

Run pip freeze > requirements.txt to generate dependencies.

4. Initialize Git (If Not Done Already)

Ensure your project is tracked in Git:

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

5. Create a Heroku App

Run:

heroku create your-app-name

If no name is provided, Heroku assigns a random one.

6. Deploy the App to Heroku

(i) Set the Remote Repository

Run:

git remote -v

If Heroku is missing, add it manually:

heroku git:remote -a your-app-name

(ii) Push Your Code to Heroku

Deploy your app:

git push heroku main

If using master instead of main:

git push heroku master

7. Scale the App

Ensure at least one web process is running:

heroku ps:scale web=1

8. Open the App

Run:

heroku open

This launches your app in a browser.

9. Check Logs for Errors

If deployment fails, check logs:

heroku logs --tail

10. Setting Environment Variables

Use:

heroku config:set VAR_NAME=value

To view all variables:

heroku config

11. Database Setup (Optional)

For PostgreSQL, enable Heroku’s free Postgres addon:

heroku addons:create heroku-postgresql:hobby-dev

Retrieve the database URL:

heroku config | grep DATABASE_URL

12. Continuous Deployment with GitHub (Optional)

Instead of manually pushing, link Heroku to your GitHub repository:

heroku git:remote -a your-app-name

Then, enable automatic deployment from the Heroku dashboard under Deploy → GitHub.

Conclusion

Your app should now be live on Heroku 🎉! You can scale, manage, and monitor it using Heroku CLI or the Heroku dashboard.