vue-cli/docs/guide/mode-and-env.md

Environment Variables and Modes

You can specify env variables by placing the following files in your project root:

.env                # loaded in all cases
.env.local          # loaded in all cases, ignored by git
.env.[mode]         # only loaded in specified mode
.env.[mode].local   # only loaded in specified mode, ignored by git

An env file simply contains key=value pairs of environment variables:

FOO=bar
VUE_APP_SECRET=secret

Loaded variables will become available to all vue-cli-service commands, plugins and dependencies.

::: tip Env Loading Priorities

An env file for a specific mode (e.g. .env.production) will take higher priority than a generic one (e.g. .env).

In addition, environment variables that already exist when Vue CLI is bootstrapped have the highest priority and will not be overwritten by .env files. :::

::: warning NODE_ENV If you have a default NODE_ENV in your environment, you should either remove it or explicitly set NODE_ENV when running vue-cli-service commands. :::

Modes

Mode is an important concept in Vue CLI projects. By default, there are three modes in a Vue CLI project:

• development is used by vue-cli-service serve
• production is used by vue-cli-service build and vue-cli-service test:e2e
• test is used by vue-cli-service test:unit

Note that a mode is different from NODE_ENV, as a mode can contain multiple environment variables. That said, each mode does set NODE_ENV to the same value by default - for example, NODE_ENV will be set to "development" in development mode.

You can set environment variables only available to a certain mode by postfixing the .env file. For example, if you create a file named .env.development in your project root, then the variables declared in that file will only be loaded in development mode.

You can overwrite the default mode used for a command by passing the --mode option flag. For example, if you want to use development variables in the build command, add this to your package.json scripts:

"dev-build": "vue-cli-service build --mode development",

Example: Staging Mode

Assuming we have an app with the following .env file:

VUE_APP_TITLE=My App

And the following .env.staging file:

NODE_ENV=production
VUE_APP_TITLE=My App (staging)

• vue-cli-service build builds a production app, loading .env, .env.production and .env.production.local if they are present;

• vue-cli-service build --mode staging builds a production app in staging mode, using .env, .env.staging and .env.staging.local if they are present.

In both cases, the app is built as a production app because of the NODE_ENV, but in the staging version, process.env.VUE_APP_TITLE is overwritten with a different value.

Using Env Variables in Client-side Code

Only variables that start with VUE_APP_ will be statically embedded into the client bundle with webpack.DefinePlugin. You can access them in your application code:

console.log(process.env.VUE_APP_SECRET)

During build, process.env.VUE_APP_SECRET will be replaced by the corresponding value. In the case of VUE_APP_SECRET=secret, it will be replaced by "secret".

In addition to VUE_APP_* variables, there are also two special variables that will always be available in your app code:

• NODE_ENV - this will be one of "development", "production" or "test" depending on the mode the app is running in.
• BASE_URL - this corresponds to the baseUrl option in vue.config.js and is the base path your app is deployed at.

All resolved env variables will be available inside public/index.html as discussed in HTML - Interpolation.

::: tip You can have computed env vars in your vue.config.js file. They still need to be prefixed with VUE_APP_. This is useful for version info

process.env.VUE_APP_VERSION = require('./package.json').version

module.exports = {
  // config
}

:::

Local Only Variables

Sometimes you might have env variables that should not be committed into the codebase, especially if your project is hosted in a public repository. In that case you should use an .env.local file instead. Local env files are ignored in .gitignore by default.

.local can also be appended to mode-specific env files, for example .env.development.local will be loaded during development, and is ignored by git.