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motdotla/dotenv

A zero-dependency Node.js module that loads environment variables from a .env file into process.env.

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What is it?

dotenv loads key-value pairs from a .env file into process.env in Node.js applications, so configuration and secrets can live outside source code, following the Twelve-Factor App approach. A project creates a .env file at its root, calls config() as early as possible, and then reads values through process.env as usual.

Beyond the core loader, the package exposes parse() to turn a string or Buffer into an object, and populate() to write parsed values into any target object. It also ships a dotenv CLI with a run subcommand that injects variables before starting a command, supporting multiple files, override and quiet flags, and a faster parser option.

The package has no dependencies and works with npm, yarn, pnpm, bun and deno. Variable expansion, command substitution and encryption are not part of this package; the README points to the companion tool dotenvx for those features.

Key features

  • 01Loads .env key-value pairs into process.env with a single config() call.
  • 02Provides parse() to convert a string or Buffer into an object.
  • 03Provides populate() to write values into a custom target object.
  • 04Includes a CLI with dotenv run to inject variables before running a command.
  • 05Supports multiple env files loaded in order, with optional override.
  • 06Has zero dependencies and works with ESM imports via dotenv/config.

Use cases

  • Keeping API keys and database URLs out of source code in a Node.js service.
  • Using different .env files for local, test and production environments.
  • Injecting environment variables into test commands or scripts with dotenv run.
  • Parsing env-formatted text in a custom tool through the parse() function.

Quick start

  1. 1

    Install dotenv with npm

    npm install dotenv --save
  2. 2

    Create a .env file in your project root with your variables

  3. 3

    Load dotenv at the start of your application

  4. 4

    Run your app with node

    node index.js

Things to know

  • Variable expansion and command substitution require the separate dotenvx tool.
  • Comments start at # unless the value is quoted, which is a breaking change from v15.

In collections

CLI & terminal tools

Topics

#nodejs#environment-variables#configuration#secrets#twelve-factor#javascript#cli#configuration-file#dotenv#env

FAQ

What is dotenv?
A zero-dependency Node.js module that loads environment variables from a .env file into process.env. dotenv loads key-value pairs from a .env file into process.env in Node.js applications, so configuration and secrets can live outside source code, following the Twelve-Factor App approach. A project creates a .env file at its root, calls config() as early as possible, and then reads values through process.env as usual.
Is dotenv free to use? What license does it have?
dotenv is open source under the BSD-2-Clause license. Check the license terms before using it in commercial products.
Is dotenv still maintained?
Actively maintained. The last commit to dotenv was on Oct 29, 2026.
What can I use dotenv for?
Keeping API keys and database URLs out of source code in a Node.js service. Using different .env files for local, test and production environments. Injecting environment variables into test commands or scripts with dotenv run. Parsing env-formatted text in a custom tool through the parse() function.
How do I install dotenv?
Install dotenv with npm: npm install dotenv --save Create a .env file in your project root with your variables Load dotenv at the start of your application Run your app with node: node index.js
Where can I get dotenv?
The source code and installation instructions are on GitHub: https://github.com/motdotla/dotenv

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