How to use the dotenv package in Node

Working with Node.js in modern application development often requires handling environment variables—special variables that contain essential configuration details such as database passwords, API keys, or other sensitive information. The excellent practice of keeping these details outside your codebase is recommended by the principles of “The Twelve-Factor App” methodology. The dotenv node package is a popular tool that helps manage environment variables efficiently, keeping your application configuration secure and succinct. This tutorial will guide you through the setup and usage of the dotenv package, so you can begin managing your app’s environment variables with ease.

Installation of dotenv

Before you can leverage the benefits of dotenv, you must first install it in your Node.js project. If you’re using npm as your package manager, you can add dotenv to your project with the following command:

npm install dotenv

Alternatively, if you prefer using Yarn, you would run:

yarn add dotenv

Once you’ve installed dotenv, you’re ready to set up your .env file and start coding secure applications.

Setting Up Your .env File

Creating a .env file is the first real step in using environment variables with the dotenv package. Here’s how you can get started:

  • Create a file named .env at the root of your project directory.
  • Inside this file, you’ll list your environment variables in KEY=value pairs. For instance, if you want to set a variable for port, you can simply write PORT=3000 in the .env file.

Remember, you should avoid including sensitive information in your .env file if it’s going to be stored in a public repository. To safeguard your secrets, ensure that .env is included in your .gitignore file to prevent it from being committed to version control systems like Git.

Integrating dotenv in Your Application

Introducing dotenv to your application is straightforward. At the starting point of your application, usually index.js or app.js, require and configure dotenv as follows:


This command will automatically load the environment variables defined in your .env file and attach them to the process.env object in Node.js. From that point on, these variables are accessible anywhere in your application using process.env.KEY where KEY is the name of your environment variable.

Accessing and Using Environment Variables

Accessing the environment variables is as simple as addressing any object’s properties in JavaScript. Here’s how you do it:

const port = process.env.PORT;

This line of code grabs the value of the PORT environment variable that you defined within your .env file and assigns it to the port constant.

When it comes to changing environment variables, modify the values directly in your .env file. There is no need to update your code unless you’re adding new variables or removing existing ones.

Security and Best Practices

Security is a primary concern when dealing with environment variables. Since your .env file can contain sensitive data, it’s of paramount importance never to commit this file to any public repository. Instead, each developer can have their .env file or, for deployment, you can use secure methods of setting these variables such as through a Continuous Integration/Continuous Deployment (CI/CD) system or a cloud service provider’s environment management tools.

Another best practice is to provide a .env.example file, which includes the names of the required environment variables without the sensitive values. This gives collaborators on your project a template to create their .env file from.

Advanced Features: Multiline Values and Comments

The dotenv package has the added benefit of supporting multiline values and comments in your .env file.

  • Multiline Values: If you need to include values that span multiple lines (like private keys), you can do so by enclosing the value in double quotes and using \n for line breaks.
  • Comments: To add comments to your .env file, start the line with a #. Comments can be on a separate line or inline with a variable declaration.
# This is a full-line comment
DB_PASSWORD=supersecret # Inline comment

These features help maintain the readability and structure of your .env files, especially as they grow in complexity and size.

Support and Community Contributions

dotenv is a community-supported module, with active contributions that continually enhance its functionality. You can find additional functions and usage options within the official documentation, including how to preload dotenv, perform variable expansion, and manage different environments for your Node.js applications.


Using dotenv in your Node.js applications is crucial for managing environment variables in a secure and organized manner. By following the steps in this tutorial, you can set up dotenv, create your .env file, and integrate environment variables into your application.

Remember that keeping your .env file secure is essential. Always include it in your project’s .gitignore and provide a .env.example template for setting up the project environment. With dotenv, you can have peace of mind knowing that your application’s configuration is well managed, secure, and scalable for different deployment environments.

Now that you understand the importance and the process of using dotenv, you can securely manage your development project’s environment variables with ease. If you have found this tutorial helpful, please feel free to share it with other developers. And, as always, if you have questions or need further assistance, consult the documentation or reach out to the community for support. Happy coding!