ExpressionEngine Docs

Main Configuration File

The main configuration settings are stored in the form of a PHP array in the system/user/config/config.php file.

This file is populated automatically during the installation process and contains the most important settings that are used by ExpressionEngine.

Settings from this file are loaded every time the system is run. This means that config overrides set in config.php always affect the system’s configuration.

At a minimum, this configuration file contains the following settings:


The installation’s ExpressionEngine version. This value is set automatically and normally should not be modified.

However if you need to run an update script again, you can modify this value to a lower version number so the system would “see” the update(s) available.

$config['app_version'] = '7.4.0';


This is the secret key used by the Encrypt service to protect sensitive data in the database. It is set automatically during the installation process. If you need to use your own key please refer to Troubleshooting guide on how to generate a new one.

$config['encryption_key'] = '26791dcd5c7cc9e569cc05b16b96235985cc9f03';


Similar to the encryption_key, but used to protected session data.

$config['session_crypt_key'] = 'd9e776dc9a5de0cd83e7c76a76756daa64ff4b8b';


The database connection details are one of the most important settings in the configuration file. The array is required to have an element with a key of expressionengine, which in turn needs to be an array with the following keys:

In addition, you can use following keys inside expressionengine:

The following keys can be specified and will be converted to PDO constants when passed to the database driver: