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The dotenv npm package is used to load environment variables from a .env file into process.env, providing a convenient way to configure your application's environment during development. It helps in managing sensitive credentials and configuration options by keeping them out of the codebase.
Basic Configuration
This is the simplest use case for dotenv. By calling `require('dotenv').config();`, dotenv reads the .env file, parses the contents, and loads them into `process.env`. After this, environment variables can be accessed using `process.env.VAR_NAME`.
require('dotenv').config();
Custom Path
If your .env file is not located in the root directory or you have multiple .env files, you can specify a custom path to your .env file using the `path` option.
require('dotenv').config({ path: '/custom/path/to/.env' });
Debugging
To assist in debugging, you can enable debug output by setting the `debug` option to `true`. This will log any errors to the console while reading the .env file.
require('dotenv').config({ debug: process.env.DEBUG });
dotenv-expand is an extension for dotenv. It allows you to have environment variables in your .env file that reference other environment variables, similar to variable expansion in Unix shell scripts. It's useful when you need to reduce redundancy in your .env files.
cross-env allows you to set and use environment variables across platforms without worrying about platform-specific differences in how environment variables are set. Unlike dotenv, which is focused on loading variables from a file, cross-env is more about providing scripts with environment variables in a cross-platform way.
env-cmd is another npm package that allows you to specify a file containing environment variable definitions and then run a given command using those variables. It's similar to dotenv but is more focused on injecting environment variables into the command line for scripts, rather than loading them into `process.env`.
Announcement 📣
From the makers that brought you Dotenv, introducing Dotenv Sync.
Sync your .env files between machines, environments, and team members.
Join the early access list.💛
Dotenv is a zero-dependency module that loads environment variables from a .env
file into process.env
. Storing configuration in the environment separate from code is based on The Twelve-Factor App methodology.
# install locally (recommended)
npm install dotenv --save
Or installing with yarn? yarn add dotenv
Usage is easy!
.env
file in the root directory of your project.# .env file
#
# Add environment-specific variables on new lines in the form of NAME=VALUE
#
DB_HOST=localhost
DB_USER=root
DB_PASS=s1mpl3
// index.js
require('dotenv').config()
console.log(process.env) // remove this after you've confirmed it working
.. or using ES6?
// index.mjs (ESM)
import 'dotenv/config' // see https://github.com/motdotla/dotenv#how-do-i-use-dotenv-with-import
import express from 'express'
process.env
now has the keys and values you defined in your .env
file.
require('dotenv').config()
...
const db = require('db')
db.connect({
host: process.env.DB_HOST,
username: process.env.DB_USER,
password: process.env.DB_PASS
})
See examples of using dotenv with various frameworks, languages, and configurations.
Dotenv exposes two functions:
config
parse
config
will read your .env
file, parse the contents, assign it to
process.env
,
and return an Object with a parsed
key containing the loaded content or an error
key if it failed.
const result = dotenv.config()
if (result.error) {
throw result.error
}
console.log(result.parsed)
You can additionally, pass options to config
.
Default: path.resolve(process.cwd(), '.env')
Specify a custom path if your file containing environment variables is located elsewhere.
require('dotenv').config({ path: '/custom/path/to/.env' })
Default: utf8
Specify the encoding of your file containing environment variables.
require('dotenv').config({ encoding: 'latin1' })
Default: false
Turn on logging to help debug why certain keys or values are not being set as you expect.
require('dotenv').config({ debug: process.env.DEBUG })
Default: false
Override any environment variables that have already been set on your machine with values from your .env file.
require('dotenv').config({ override: true })
Default: false
Turn on multiline line break parsing.
require('dotenv').config({ multiline: true })
This allows specifying multiline values in this format:
PRIVATE_KEY="-----BEGIN PRIVATE KEY-----
MIGT...
7ure...
-----END PRIVATE KEY-----"
Ensure that the value begins with a single or double quote character, and it ends with the same character.
The engine which parses the contents of your file containing environment variables is available to use. It accepts a String or Buffer and will return an Object with the parsed keys and values.
const dotenv = require('dotenv')
const buf = Buffer.from('BASIC=basic')
const config = dotenv.parse(buf) // will return an object
console.log(typeof config, config) // object { BASIC : 'basic' }
Default: false
Turn on logging to help debug why certain keys or values are not being set as you expect.
const dotenv = require('dotenv')
const buf = Buffer.from('hello world')
const opt = { debug: true }
const config = dotenv.parse(buf, opt)
// expect a debug message because the buffer is not in KEY=VAL form
Default: false
Turn on multiline line break parsing.
require('dotenv').config({ multiline: true })
This allows specifying multiline values in this format:
PRIVATE_KEY="-----BEGIN PRIVATE KEY-----
MIGT...
7ure...
-----END PRIVATE KEY-----"
You can use the --require
(-r
) command line option to preload dotenv. By doing this, you do not need to require and load dotenv in your application code. This is the preferred approach when using import
instead of require
.
$ node -r dotenv/config your_script.js
The configuration options below are supported as command line arguments in the format dotenv_config_<option>=value
$ node -r dotenv/config your_script.js dotenv_config_path=/custom/path/to/.env dotenv_config_debug=true
Additionally, you can use environment variables to set configuration options. Command line arguments will precede these.
$ DOTENV_CONFIG_<OPTION>=value node -r dotenv/config your_script.js
$ DOTENV_CONFIG_ENCODING=latin1 DOTENV_CONFIG_DEBUG=true node -r dotenv/config your_script.js dotenv_config_path=/custom/path/to/.env
.env
file not loading my environment variables successfully?Most likely your .env
file is not in the correct place. See this stack overflow.
Turn on debug mode and try again..
require('dotenv').config({ debug: true })
You will receive a helpful error outputted to your console.
.env
file?No. We strongly recommend against committing your .env
file to version
control. It should only include environment-specific values such as database
passwords or API keys. Your production database should have a different
password than your development database.
.env
files?No. We strongly recommend against having a "main" .env
file and an "environment" .env
file like .env.test
. Your config should vary between deploys, and you should not be sharing values between environments.
In a twelve-factor app, env vars are granular controls, each fully orthogonal to other env vars. They are never grouped together as “environments”, but instead are independently managed for each deploy. This is a model that scales up smoothly as the app naturally expands into more deploys over its lifetime.
The parsing engine currently supports the following rules:
BASIC=basic
becomes {BASIC: 'basic'}
#
are treated as comments#
marks the beginning of an inline comment (unless when the value is wrapped in quotes)EMPTY=
becomes {EMPTY: ''}
)JSON={"foo": "bar"}
becomes {JSON:"{\"foo\": \"bar\"}"
)trim
) (FOO= some value
becomes {FOO: 'some value'}
)SINGLE_QUOTE='quoted'
becomes {SINGLE_QUOTE: "quoted"}
)FOO=" some value "
becomes {FOO: ' some value '}
)MULTILINE="new\nline"
becomes{MULTILINE: 'new
line'}
By default, we will never modify any environment variables that have already been set. In particular, if there is a variable in your .env
file which collides with one that already exists in your environment, then that variable will be skipped.
If instead, you want to override process.env
use the override
option.
require('dotenv').config({ override: true })
React has dotenv built in but with a quirk. Preface your environment variables with REACT_APP_
. See this stack overflow for more details.
Yes! dotenv.config()
returns an object representing the parsed .env
file. This gives you everything you need to continue setting values on process.env
. For example:
const dotenv = require('dotenv')
const variableExpansion = require('dotenv-expand')
const myEnv = dotenv.config()
variableExpansion(myEnv)
import
?Simply..
// index.mjs (ESM)
import 'dotenv/config' // see https://github.com/motdotla/dotenv#how-do-i-use-dotenv-with-import
import express from 'express'
A little background..
When you run a module containing an
import
declaration, the modules it imports are loaded first, then each module body is executed in a depth-first traversal of the dependency graph, avoiding cycles by skipping anything already executed.
What does this mean in plain language? It means you would think the following would work but it won't.
// errorReporter.mjs
import { Client } from 'best-error-reporting-service'
export default new Client(process.env.API_KEY)
// index.mjs
import dotenv from 'dotenv'
dotenv.config()
import errorReporter from './errorReporter.mjs'
errorReporter.report(new Error('documented example'))
process.env.API_KEY
will be blank.
Instead the above code should be written as..
// errorReporter.mjs
import { Client } from 'best-error-reporting-service'
export default new Client(process.env.API_KEY)
// index.mjs
import 'dotenv/config'
import errorReporter from './errorReporter.mjs'
errorReporter.report(new Error('documented example'))
Does that make sense? It's a bit unintuitive, but it is how importing of ES6 modules work. Here is a working example of this pitfall.
There are also 2 alternatives to this approach:
node --require dotenv/config index.js
(Note: you do not need to import
dotenv with this approach)config
first as outlined in this comment on #133Try dotenv-expand
Try dotenv cli
See CONTRIBUTING.md
See CHANGELOG.md
These npm modules depend on it.
Projects that expand it often use the keyword "dotenv" on npm.
FAQs
Loads environment variables from .env file
The npm package dotenv receives a total of 33,895,420 weekly downloads. As such, dotenv popularity was classified as popular.
We found that dotenv demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 4 open source maintainers collaborating on the project.
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
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