Registering an Extbase frontend plugin 

Configuring the plugin dispatcher 

ExtensionUtility::configurePlugin() registers which controller actions are allowed and generates the TypoScript to route requests to the Extbase dispatcher. Call it in ext_localconf.php:

use MyVendor\MyExtension\Controller\ConferenceController;
use TYPO3\CMS\Extbase\Utility\ExtensionUtility;

defined('TYPO3') or die();

ExtensionUtility::configurePlugin(
    'MyExtension',
    'ConferenceList',
    [ConferenceController::class => 'list, show, create'],
    [ConferenceController::class => 'create'],
);

The four arguments are:

1. Extension name — the extension key in UpperCamelCase (my_extension → MyExtension).
2. Plugin name — a unique UpperCamelCase identifier for this plugin inside the extension. Combined with the extension name, it forms the plugin signature used in TypoScript and routing (myextension_conferencelist). The combined length must not exceed 32 characters. snake_case is also accepted and normalised internally, but UpperCamelCase is the convention.
3. Allowed controller actions — an array mapping controller class names to a comma-separated list of action names. The first entry and its first action are the default. Only actions listed here are available via this plugin.
4. Non-cacheable actions — a subset of the above defining output that must not be stored in the page cache. See Non-cacheable Extbase plugin actions and developer responsibility for the implications.

Registering the plugin in the backend 

ExtensionUtility::registerPlugin() adds the plugin to the list of available content element types in the backend. Call it in Configuration/TCA/Overrides/tt_content.php:

use TYPO3\CMS\Extbase\Utility\ExtensionUtility;

defined('TYPO3') or die();

ExtensionUtility::registerPlugin(
    'MyExtension',
    'ConferenceList',
    'my_extension.db:plugin.conferencelist.title',
    'my-extension-conference-list',
    'plugins',
    'my_extension.db:plugin.conferencelist.description',
    'EXT:my_extension/Configuration/FlexForms/ConferenceList.xml',
);

The arguments are:

1. Extension name — same as in configurePlugin() .
2. Plugin name — same as in configurePlugin() . The two values must match exactly.
3. Plugin title — label shown in the backend content element wizard. Use a translatable label reference. The example uses the translation domain syntax (extension_key.file:label_key), which is shorter than the legacy LLL:EXT: path syntax. Both are equivalent and interchangeable.
4. Plugin icon — an icon identifier registered via the Icon API, or a path prefixed with EXT:. Optional. Defaults to the generic plugin icon.
5. Group — groups the plugin in the content element wizard. Common values are 'plugins' (generic plugin group) or a custom group name matching your extension.
6. Description — optional longer text shown in the content element wizard.
7. FlexForm — path to a FlexForm XML file that adds configurable fields to the content element in the backend, for example 'EXT:my_extension/Configuration/FlexForms/ConferenceList.xml'. Optional. Omit if the plugin needs no backend configuration form.

Both calls must use the same extension name and plugin name. A mismatch means the dispatcher will not find the controller actions registered for that plugin.

How the plugin configuration is assembled 

When an Extbase frontend plugin handles a request, the framework assembles a single configuration array from three layers, each able to override the previous:

1. plugin.tx_myextension — extension-wide defaults, applied to every plugin of this extension.
2. plugin.tx_myextension_myplugin — plugin-specific values, override the extension-wide layer.
3. FlexForm data — values the editor entered in the content element's plugin tab. These have the highest priority and override both TypoScript layers. Only settings , persistence , and view keys are merged from the FlexForm.

The resulting array has three top-level keys that Extbase uses directly:

• settings — arbitrary key/value pairs available as $this->settings in the controller and as {settings} in Fluid templates (auto-assigned by the framework for frontend plugins).
• persistence — controls record loading; the most relevant sub-key is storagePid , which limits which page(s) the repository queries.
• view — overrides template file resolution via templateRootPaths , layoutRootPaths , and partialRootPaths .

TypoScript plugin object path 

configurePlugin() generates a TypoScript object for the plugin at:

plugin.tx_<extensionkey>_<pluginname>

Both parts are lowercase; underscores are removed from the extension key. For the example above that is plugin.tx_myextension_conferencelist . A full example covering all three configuration keys:

plugin.tx_myextension_conferencelist {
    view {
        templateRootPaths.10 = EXT:my_extension/Resources/Private/Templates/
    }
    persistence {
        storagePid = {$plugin.tx_myextension_conferencelist.persistence.storagePid}
    }
    settings {
        itemsPerPage = 10
    }
}

To find the exact TypoScript path of a plugin, open the TYPO3 backend, navigate to a site or page containing the plugin, and inspect the computed TypoScript tree in Site Management > TypoScript.