Since version 6.0, TYPO3 CMS uses PHP namespaces for all classes in the Core.

The general structure of namespaces is the following:


For the Core, the vendor name is TYPO3\CMS and the package name corresponds to a system extension.

All classes must be located inside the Classes folder at the root of the (system) extension. The category name may contain several segments that correspond to the path inside the Classes folder.

Finally the class name is the same as the corresponding file name, without the .php extension.

"UpperCamelCase" is used for all segments.


See the chapter about 'ClassAliasMap.php' in the 6.2 documentation.. It may help you with migrating code from old to new conventions.

Core example

The good old t3lib_div class has been renamed to:


This means that the class is now found in the "core" system extension, in folder Classes/Utility, in a file named GeneralUtility.php.

Usage in extensions

Extension developers are free to use their own vendor name. Important: It may consist of one segment only. Vendor names must start with an uppercase character and are usually written in UpperCamelCase style. In order to avoid problems with different filesystems, only the characters a-z, A-Z, 0-9 and the dash sign "-" are allowed for package names – don't use special characters:

// good vendor name:

// wrong vendor name:


The vendor name TYPO3\CMS is reserved and may not be used by extensions!

The package name corresponds to the extension key. Underscores in the extension key are removed in the namespace and replaced by upper camel-case. So extension key:


would become:


in the namespace.

As mentioned above, all classes must be located in the Classes folder inside your extension. All sub-folders translate to a segment of the category name and the class name is the file name without the .php extension.

Looking at the "examples" extension, class:


corresponds to namespace:


Inside the class, the namespace is declared as:

namespace Documentation\Examples\Controller;

Namespaces in Extbase

When registering components in Extbase, the vendor name must be used on top of the extension key.

For a backend module:

    // ...

For a frontend module:

    // ...


  • Do not forget the dot after the vendor name.
  • Do not use dots inside the vendor name.

Namespaces for test classes

As for ordinary classes, namespaces for test classes start with a vendor name followed by the extension key.

All test classes reside in a Tests folder and thus the third segment of the namespace must be "Tests". Unit tests are located in a Unit folder which is the fourth segment of the namespace. Any further subfolders will be subsequent segments.

So a test class in EXT:foo_bar_baz/Tests/Unit/Bla/ will have as namespace \Vendor\FooBarBaz\Tests\Unit\Bla.

Creating instances

When creating instances using \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance() the leading backslash must be omitted and all other backslashes escaped, even when using single quotes. Thus the following code is correct:

$contentObject = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer::class);

There is no need to use require() or include() statements. All classes that follow namespace conventions will automatically located and included by the autoloader.


For more information about PHP namespaces in general, you may want to refer to the PHP documentation and in particular the Namespaces FAQ.