Dotenv is a zero-dependency module that loads environment variables from a `.env` file into [`process.env`](https://nodejs.org/docs/latest/api/process.html#process_process_env). Storing configuration in the environment separate from code is based on [The Twelve-Factor App](https://12factor.net/config) methodology.
Create a `.env` file in the root of your project (if using a monorepo structure like `apps/backend/app.js`, put it in the root of the folder where your `app.js` process runs):
```dosini
S3_BUCKET="YOURS3BUCKET"
SECRET_KEY="YOURSECRETKEYGOESHERE"
```
As early as possible in your application, import and configure dotenv:
```javascript
require('dotenv').config()
console.log(process.env) // remove this after you've confirmed it is working
Comments may be added to your file on their own line or inline:
```dosini
# This is a comment
SECRET_KEY=YOURSECRETKEYGOESHERE # comment
SECRET_HASH="something-with-a-#-hash"
```
Comments begin where a `#` exists, so if your value contains a `#` please wrap it in quotes. This is a breaking change from `>= v15.0.0` and on.
### Parsing
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.
> Note: Consider using [`dotenvx`](https://github.com/dotenvx/dotenvx) instead of preloading. I am now doing (and recommending) so.
>
> It serves the same purpose (you do not need to require and load dotenv), adds better debugging, and works with ANY language, framework, or platform. – [motdotla](https://github.com/motdotla)
You can use the `--require` (`-r`) [command line option](https://nodejs.org/api/cli.html#-r---require-module) to preload dotenv. By doing this, you do not need to require and load dotenv in your application code.
You need to keep `.env` files in sync between machines, environments, or team members? Use [dotenvx](https://github.com/dotenvx/dotenvx) to encrypt your `.env` files and safely include them in source control. This still subscribes to the twelve-factor app rules by generating a decryption key separate from code.
### Multiple Environments
Use [dotenvx](https://github.com/dotenvx/dotenvx) to generate `.env.ci`, `.env.production` files, and more.
### Deploying
You need to deploy your secrets in a cloud-agnostic manner? Use [dotenvx](https://github.com/dotenvx/dotenvx) to generate a private decryption key that is set on your production server.
## 🌴 Manage Multiple Environments
Use [dotenvx](https://github.com/dotenvx/dotenvx)
Run any environment locally. Create a `.env.ENVIRONMENT` file and use `--env-file` to load it. It's straightforward, yet flexible.
By default, `config` will look for a file called .env in the current working directory.
Pass in multiple files as an array, and they will be parsed in order and combined with `process.env` (or `option.processEnv`, if set). The first value set for a variable will win, unless the `options.override` flag is set, in which case the last value set will win. If a value already exists in `process.env` and the `options.override` flag is NOT set, no changes will be made to that value.
Override any environment variables that have already been set on your machine with values from your .env file(s). If multiple files have been provided in `option.path` the override will also be used as each file is combined with the next. Without `override` being set, the first value wins. With `override` set the last value wins.
```js
require('dotenv').config({ override: true })
```
##### processEnv
Default: `process.env`
Specify an object to write your secrets to. Defaults to `process.env` environment variables.
The engine which populates the contents of your .env file to `process.env` is available for use. It accepts a target, a source, and options. This is useful for power users who want to supply their own objects.
Turn on logging to help debug why certain keys or values are not being populated as you expect.
##### override
Default: `false`
Override any environment variables that have already been set.
## ❓ FAQ
### Why is the `.env` file not loading my environment variables successfully?
Most likely your `.env` file is not in the correct place. [See this stack overflow](https://stackoverflow.com/questions/42335016/dotenv-file-is-not-loading-environment-variables).
Turn on debug mode and try again..
```js
require('dotenv').config({ debug: true })
```
You will receive a helpful error outputted to your console.
We recommend creating one `.env` file per environment. Use `.env` for local/development, `.env.production` for production and so on. This still follows the twelve factor principles as each is attributed individually to its own environment. Avoid custom set ups that work in inheritance somehow (`.env.production` inherits values form `.env` for example). It is better to duplicate values if necessary across each `.env.environment` file.
> 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.
- whitespace is removed from both ends of unquoted values (see more on [`trim`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/Trim)) (`FOO= some value ` becomes `{FOO: 'some value'}`)
- single and double quoted values are escaped (`SINGLE_QUOTE='quoted'` becomes `{SINGLE_QUOTE: "quoted"}`)
- single and double quoted values maintain whitespace from both ends (`FOO=" some value "` becomes `{FOO: ' some value '}`)
- double quoted values expand new lines (`MULTILINE="new\nline"` becomes
```
{MULTILINE: 'new
line'}
```
- backticks are supported (`` BACKTICK_KEY=`This has 'single' and "double" quotes inside of it.` ``)
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.
### How come my environment variables are not showing up for React?
Your React code is run in Webpack, where the `fs` module or even the `process` global itself are not accessible out-of-the-box. `process.env` can only be injected through Webpack configuration.
If you are using [`react-scripts`](https://www.npmjs.com/package/react-scripts), which is distributed through [`create-react-app`](https://create-react-app.dev/), it has dotenv built in but with a quirk. Preface your environment variables with `REACT_APP_`. See [this stack overflow](https://stackoverflow.com/questions/42182577/is-it-possible-to-use-dotenv-in-a-react-project) for more details.
If you are using other frameworks (e.g. Next.js, Gatsby...), you need to consult their documentation for how to inject environment variables into the client.
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:
> 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.
>
> – [ES6 In Depth: Modules](https://hacks.mozilla.org/2015/08/es6-in-depth-modules/)
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](https://github.com/dotenv-org/examples/tree/master/usage/dotenv-es6-import-pitfall).
2. Create a separate file that will execute `config` first as outlined in [this comment on #133](https://github.com/motdotla/dotenv/issues/133#issuecomment-255298822)
### Why am I getting the error `Module not found: Error: Can't resolve 'crypto|os|path'`?
You are using dotenv on the front-end and have not included a polyfill. Webpack <5usedtoincludetheseforyou.Dothefollowing:
```bash
npm install node-polyfill-webpack-plugin
```
Configure your `webpack.config.js` to something like the following.
### What if I accidentally commit my `.env` file to code?
Remove it, [remove git history](https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/removing-sensitive-data-from-a-repository) and then install the [git pre-commit hook](https://github.com/dotenvx/dotenvx#pre-commit) to prevent this from ever happening again.
```
brew install dotenvx/brew/dotenvx
dotenvx precommit --install
```
### How can I prevent committing my `.env` file to a Docker build?
Use the [docker prebuild hook](https://dotenvx.com/docs/features/prebuild).
