process.env for environment variables in Node.js - Mini Project: Build & Apply

Using process.env for Environment Variables in Node.js

📖 Scenario: You are building a simple Node.js app that needs to use secret keys and settings without hardcoding them in your code. Environment variables help keep these values safe and easy to change.

🎯 Goal: Learn how to create environment variables and access them in your Node.js app using process.env.

📋 What You'll Learn

Create a .env file with specific environment variables

Load environment variables using the dotenv package

Access environment variables in your Node.js code using process.env

Use environment variables to configure app settings

💡 Why This Matters

🌍 Real World

Environment variables are used to keep sensitive data like API keys and passwords out of your code. This helps keep your app secure and flexible.

💼 Career

Knowing how to use process.env and environment variables is essential for backend developers and anyone deploying apps to real servers or cloud platforms.

1

Create a .env file with environment variables

Create a file named .env in your project root. Inside it, write these exact lines:
API_KEY=12345abcde
PORT=3000

Node.js

# Create a .env file with API_KEY and PORT
# Your code here

Need a hint?

The .env file stores key-value pairs like KEY=value. Make sure there are no spaces around the equals sign.

2

Install and configure dotenv package

In your Node.js project, install the dotenv package by running npm install dotenv. Then, in your main file index.js, add this line at the very top:
require('dotenv').config();

Node.js

require('dotenv').config();
// Your code here

Need a hint?

This line loads the variables from your .env file into process.env.

3

Access environment variables in your code

In index.js, create two constants named apiKey and port. Assign them the values from process.env.API_KEY and process.env.PORT respectively.

Node.js

require('dotenv').config();

const apiKey = process.env.API_KEY;
const port = process.env.PORT;
// Your code here

Need a hint?

Use process.env.VARIABLE_NAME to get the value of an environment variable.

4

Use environment variables to configure your app

Add a simple console log that outputs: Server running on port {port} with API key {apiKey} using template literals and the constants port and apiKey.

Node.js

require('dotenv').config();

const apiKey = process.env.API_KEY;
const port = process.env.PORT;

// Your code here

Need a hint?

Use backticks ` and ${variable} to insert variables inside strings.