How to Deploy a NodeJS REST API to Heroku

Node.js is a powerful tool for building fast, scalable APIs. Heroku makes deployment easy, turning our local project into a live, running application in minutes. In this post, we will deploy a simple Node.js REST API to Heroku from an Ubuntu server.

Prerequisites

Before we begin, ensure that:

Node.js and npm are installed.
Git is installed.
A Heroku account is created.
The Heroku CLI is installed.

Create a REST API in Node.js

If you already have an API in Node.js skip this step. If you don’t have one, check out this post on How to create a REST API in NodeJS to have an API for this test

Deploy to Heroku

We need to make a few changes before deploying to Heroku.One of the changes we need to make is, in the package.json file of our app, to tell Heroku exactly what we want it to run on, because in this case we're using Node.js and we can give it the version of Node that we want to run. So if you want to use a specific version of Node, you can put it in here.

And that will mean that our development environment and our production environment can be synchronized. Heroku has support for a bunch of different versions.

So if you want to use a specific version of Node.js, we can add the following to the package.json file:

{
    ...
    "engines": "22.x"
}

And that will mean that our development environment and our production environment can be synchronized

Add Procfile

Ensure the app runs on Heroku by adding a Procfile in the root directory:

echo "web: node server.js" > Procfile

A Procfile in Heroku is a plain text file that defines the processes to run in a Heroku application. It specifies how to start the app, typically using web: node server.js for a Node.js app. The Procfile is essential because it tells Heroku how to launch the application and ensures the correct process runs in the dyno environment.

The name web is important because it declares that this single process type attaches to Heroku’s HTTP routing stack and receives web traffic when deployed

Initialize Git

Run the following commands to set up Git:

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

Login to Heroku

heroku login

If you need to do everything from the terminal then you can provide credentials with the command

heroku login -i

That will prompt you for the username and password. If your account is protected by MFA it will fail. Use the API key of your account as your password.

Create a Heroku app

Create a new Heroku app:

heroku create hello-nodejs-api --region eu

Where:

hello-nodejs-api is the unique app name.
--region eu - Specifies the region for deployment (i.e. eu, us)

When we create a heroku app with this command, we also create a Git remote called heroku that is associated with our local Git repository.

Deploy the code

Push your git repository to heroku and heroku will deploy the code for us

git push heroku main

If your default branch is master, use:

git push heroku master

At the end of the deployment the output of the terminal will tell us the URL where the app has been deployed. Copy it, we’ll use it to test the app

Open the app

If you have available the web browser you can directly open the app with the command:

heroku open

If not, use the URL we copied in the previous step and use curl:

curl https://[YOUR_APP_DNS_NAME]/hello

Your API is now live! 🎉