Our Express app is a very simple API that listens on port 3000. And has a single endpoint of root, which returns a JSON message of Hello World.

Create a new folder named hello-express-app and cd into it.

mkdir hello-express-app && cd hello-express-app

Now that we are inside our project, let's initialize our project with npm, and install express and dotenv package.

npm init -y
npm install express dotenv

Create a file named index.js and paste the below code