Environmental Configuration

Some settings should be defined on a per-environment basis. For example, when developing locally, you may want your site’s base URL to be http://my-project.test, but on production it should be https://my-project.com.

Control Panel Settings

Some settings in the Control Panel can be set to environment variables (like the ones defined in your .env file):

  • General Settings
    • System Name
  • Sites
    • Base URL
  • Sections
    • Preview Target URIs
  • Asset Volumes
    • Base URL
    • File System Path (Local)
  • Email
    • System Email Address
    • Sender Name
    • HTML Email Template
    • Username (Gmail and SMTP)
    • Password (Gmail and SMTP)
    • Host Name (SMTP)
    • Port (Port)

To set these settings to an environment variable, type $ followed by the environment variable’s name.

A volume’s Base URL setting

Only the environment variable’s name will be stored in your database or project config, so this is a great way to set setting values that may change per-environment, or contain sensitive information.


Plugins can add support for environment variables and aliases in their settings as well. See Environmental Settings to learn how.

Using Aliases in Control Panel Settings

Some of these settings—the ones that store a URL or a file system path—can also be set to aliases, which is helpful if you just want to store a base URL or path in an environment variable, and append additional segments onto it.

For example, you can define a ROOT_URL environment variable that is set to the root URL of your site:

# -- .env --

Then create a @rootUrl alias that references it:

// -- config/general.php --
'aliases' => [
    '@rootUrl' => getenv('ROOT_URL'),

Then you could go into your User Photos volume’s settings (for example) and set its Base URL to @rootUrl/images/user-photos.

Config Files

You can set your general config settings, database connection settings, and other PHP config files to environment variables using PHP’s getenv() function:

# -- .env --
// -- config/general.php --
'cpTrigger' => getenv('CP_TRIGGER') ?: 'admin',

Multi-Environment Configs

Craft’s PHP config files can optionally define separate config settings for each individual environment.

// -- config/general.php --
return [
    // Global settings
    '*' => [
        'omitScriptNameInUrls' => true,

    // Dev environment settings
    'dev' => [
        'devMode' => true,

    // Production environment settings
    'production' => [
        'cpTrigger' => 'secret-word',

The '*' key is required here so Craft knows to treat it as a multi-environment key, but the other keys are up to you. Craft will look for the key(s) that match the CRAFT_ENVIRONMENT PHP constant, which should be defined by your web/index.php file. (Your server’s hostname will be used as a fallback.)

By default, new Craft 3 projects will define the CRAFT_ENVIRONMENT constant using an environment variable called ENVIRONMENT, which is defined in the .env file:

# -- .env --
// -- web/index.php --
define('CRAFT_ENVIRONMENT', getenv('ENVIRONMENT') ?: 'production');