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Using .env Files in Node.js

In a Node.js application, environment variables can be managed using a .env file. Typically, the dotenv package is used to load these variables at runtime.

Steps to Use .env in Node.js:​

Install the dotenv package:​

npm install dotenv

create a .env file in the root of your project.​

Example .env file:

example.env
PORT=3000
DATABASE_URL=mongodb://localhost:27017/myapp
SECRET_KEY=mysecretkey

Load the .env file in your application:​

In your entry file (e.g., app.js or index.js), load the environment variables using dotenv:

app.js
require('dotenv').config();

const port = process.env.PORT || 3000;
const dbUrl = process.env.DATABASE_URL;
const secretKey = process.env.SECRET_KEY;

console.log(`Server is running on port: ${port}`);

Access the environment variables:​

app.js
console.log(process.env.PORT);  // Output: 3000