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Declaration File (ext_emconf.php)

-- required

The ext_emconf.php is the single most important file in an extension. Without it, the Extension Manager (EM) will not detect the extension, much less be able to install it. This file contains a declaration of what the extension is or does for the EM. The only thing included is an associative array, $EM_CONF[extension key]. The keys are described in the table below.

This file is overwritten, when extensions are imported from the online repository. So don't write your custom code in this file - only change values in the $EM_CONF array if needed.

    'title' => 'Extension title',
    'description' => 'Extension description',
    'category' => 'plugin',
    'author' => 'John Doe',
    'author_email' => '',
    'author_company' => 'some company',
    'state' => 'stable',
    'clearCacheOnLoad' => 0,
    'version' => '1.0.0',
    'constraints' => [
        'depends' => [
            'typo3' => '11.0.0-11.99.99',
        'conflicts' => [
        'suggests' => [

$_EXTKEY is set globally and contains the extension key.


Due to limitations to the TER (TYPO3 Extension Repository), $_EXTKEY should be used here and not a constant or a string.


Data type



string, required

The name of the extension in English.


string, required

Short and precise description in English of what the extension does and for whom it might be useful.



Version of the extension. Automatically managed by EM / TER. Format is [int].[int].[int]



Which category the extension belongs to:

  • be

    Backend (Generally backend-oriented, but not a module)

  • module

    Backend modules (When something is a module or connects with one)

  • fe

    Frontend (Generally frontend oriented, but not a "true" plugin)

  • plugin

    Frontend plugins (Plugins inserted as a "Insert Plugin" content element)

  • misc

    Miscellaneous stuff (Where not easily placed elsewhere)

  • services

    Contains TYPO3 services

  • templates

    Contains website templates

  • example

    Example extension (Which serves as examples etc.)

  • doc

    Documentation (e.g. tutorials, FAQ's etc.)

  • distribution

    Distribution, an extension kickstarting a full site



List of requirements, suggestions or conflicts with other extensions or TYPO3 or PHP version. Here's how a typical setup might look:

'constraints' => [
    'depends' => [
        'typo3' => '9.5.0-10.4.99',
        'php' => '7.2.0-7.4.99'
    'conflicts' => [
        'templavoilaplus' => ''
    'suggests' => [
        'news' => '7.3.0-0.0.0'

List of extensions that this extension depends on. Extensions defined here will be loaded before the current extension.


List of extensions which will not work with this extension.


List of suggestions of extensions that work together or enhance this extension. Extensions defined here will be loaded before the current extension. Dependencies take precedence over suggestions. Loading order especially matters when overriding TCA or SQL of another extension.

The above example indicates that the extension depends on a version of TYPO3 between 9.5 and 10.4 (as only bug and security fixes are integrated into TYPO3 when the last digit of the version changes, it is safe to assume it will be compatible with any upcoming version of the corresponding branch, thus .99). Also the extension has been tested and is known to work properly with PHP 7.2, 7.3 and 7.4. It will conflict with "templavoilaplus" (any version) and it is suggested that it might be worth installing "news" (version at least 7.3.0). Be aware that you should add at least the TYPO3 and PHP version constraints to this file to make sure everything is working properly.



Which state is the extension in

  • alpha

    Alpha state is used for very initial work, basically the state is has during the very process of creating its foundation.

  • beta

    Under current development. Beta extensions are functional but not complete in functionality. Most likely beta-extensions will not be reviewed.

  • stable

    Stable extensions are complete, mature and ready for production environment. You will be approached for a review. Authors of stable extensions carry a responsibility to maintain and improve them.

  • experimental

    Experimental state is useful for anything experimental - of course. Nobody knows if this is going anywhere yet... Maybe still just an idea.

  • test

    Test extension, demonstrates concepts, etc.

  • obsolete

    The extension is obsolete or deprecated. This can be due to other extensions solving the same problem but in a better way or if the extension is not being maintained anymore.

  • excludeFromUpdates

    This state makes it impossible to update the extension through the Extension Manager (neither by the Update mechanism, nor by uploading a newer version to the installation). This is very useful if you made local changes to an extension for a specific installation and don't want any admin to overwrite them.



If set, the EM will request the cache to be cleared when this extension is loaded.



Author name


email address

Author email address



Author company



To get better class loading support for websites in non-composer mode the following information can be provided.

Extensions having one folder with classes or single files

Considering you have an Extbase extension (or an extension where all classes and interfaces reside in a Classes folder) or single classes you can simply add the following to your ext_emconf.php file:

'autoload' => [
   'classmap' => [

Extensions using namespaces

If the extension has namespaced classes following the PSR-4 standard, then you can add the following to your ext_emconf.php file:

'autoload' => [
   'psr-4' => [
      'Vendor\\ExtName\\' => 'Classes'


The prefix must end with a backslash.



Same as the configuration "autoload" but it is only used if the ApplicationContext is set to Testing.

Deprecated Configuration

The following fields have become deprecated since this TYPO3 version. They have no effect any more.

  • (No new entries are listed here. For formerly deprecated fiels: see older versions of this page).