Extension loading order

In TYPO3, the order in which extensions are loaded can impact system behavior. This is especially important when an extension overrides, extends, or modifies the functionality of another. TYPO3 initializes extensions in a defined order, and if dependencies are not loaded beforehand, it can lead to unintended behavior.

Defining the loading order via file composer.json

Deprecated since version 14.2

File ext_emconf.php is deprecated, the loading order is defined in the composer.json file for all installation methods.

Extensions and dependencies are installed based on the configuration in the composer.json file.

For example, if an extension relies on or modifies functionality provided by the typo3/cms-felogin system extension, the dependency should be defined as follows:

Excerpt of EXT:my_extension/composer.json

"require": {
    "typo3/cms-felogin": "^13.4 || ^14.3"
}

This ensures that TYPO3 loads the extension after the typo3/cms-felogin system extension.

Instead of require, extensions can also use the suggest section. Suggested extensions, if installed, are loaded before the current one — just like required ones — but without being mandatory.

A typical use case is suggesting an extension that provides optional widgets, such as for typo3/cms-dashboard .