--- title: "Naming conventions" manual: "TYPO3 Explained" version: "11.5" permalink: "https://docs.typo3.org/permalink/t3coreapi:extension-naming@11.5" source: "ExtensionArchitecture/BestPractises/NamingConventions.rst" rendered: "2026-10-21T15:30:00+00:00" --- > [!WARNING] > **Attention** > > TYPO3 v11 has reached end-of-life as of October 31th 2024 and > is no longer being maintained. Use the version switcher on the top > left of this page to select documentation for a supported version of TYPO3. > > Need more time before upgrading? > You can purchase Extended Long Term Support (ELTS) for TYPO3 v11 here: > [TYPO3 ELTS](https://typo3.com/services/extended-support-elts). # Naming conventions {#extension-naming} The first thing you should decide on is the [extension key](https://docs.typo3.org/permalink/t3coreapi:extension-key@11.5) for your extension and the vendor name. A significant part of the names below are based on the extension key. > [!TIP] > Some of the names, such as extension key or vendor name, will be spelled differently, > depending on where they are used, for example: > > - underscores (`_`) in the extension key should be replaced by dashes (`-`), when used in the > package name in the file `composer.json` (e.g. `cool_shop` becomes `/cool-shop`) > - underscores in the extension key should be removed by converting the extension key > to UpperCamelCase in namespaces (e.g. `cool_shop` becomes `\MyVendor\CoolShop`) ## Abbreviations & Glossary {#extension-naming-extensionname} - **UpperCamelCase** [UpperCamelCase](https://en.wikipedia.org/wiki/Camel_case) begins with a capital letter and begins all following subparts of a word with a capital letter. The rest of each word is in lowercase with no spaces, e.g. `CoolShop`. - **lowerCamelCase** [lowerCamelCase](https://en.wikipedia.org/wiki/Camel_case) is the same as UpperCamelCase, but begins with a lowercase letter. - **TER** The ["TYPO3 Extension Repository"](https://extensions.typo3.org/): A catalogue of extensions where you can find information about extensions and where you can search and filter by TYPO3 version etc. Once registered on [https://my.typo3.org](https://my.typo3.org), you can login and register an extension key for your extension in [https://extensions.typo3.org](https://extensions.typo3.org) **My Extensions**. - **extkey** The extension key as is (e.g. 'my_extension'). - **extkeyprefix** The extension key with stripped away underscores (e.g. extkey='my_extension' becomes extkeyprefix='myextension'). - **ExtensionName** The term ExtensionName means the extension key in UpperCamelCase. Example: for an extkey `bootstrap_package` the ExtensionName would be `BootstrapPackage`. The ExtensionName is used as first parameter in the Extbase methods `ExtensionUtility::configurePlugin()` or `ExtensionUtility::registerModule()`. - **modkey** The backend module key. - **Public extensions** Public extensions are publicly available. They are usually registered in TER and available via [Packagist](https://packagist.org/). - **Private extensions** These are not published to the TER or Packagist. Some of these "Conventions" are actually mandatory, meaning you **will** most likely run into problems if you do not adhere to them. We **very strongly recommend** to always use these naming conventions. Hard requirements are emphasized by using the words MUST, etc. as specified in [RFC 2119](https://www.ietf.org/rfc/rfc2119.txt). SHOULD or MAY indicate a soft requirement: strongly recommended but will usually work, even if you do not follow the conventions. > [!TIP] > If you study the naming conventions closely you will find that > they are complicated due to varying rules derived from the extkey, > if the extkey contains underscores. Sometimes the underscores are > stripped off, sometimes not, sometimes a name in UpperCamelCase is created. > > The best practice you can follow is to *avoid using underscores* in > your extensions keys altogether. That will make the rules simpler and is > highly recommended. ## Extension key (extkey) {#naming-conventions-extkey} The extension key (extkey) is used **as is** in: - directory name of extension in `typo3conf/ext` (or `typo3/sysext` for system extensions) Derived names are: - package name in `composer.json` `/`. Underscores (`_`) should be replaced by dashes (`-`) - namespaces: Underscores in the extension key are removed by converting the extension key to UpperCamelCase in namespaces (e.g. `cool_shop` becomes `MyVendorCoolShop`). > [!IMPORTANT] > If you plan to [publish your extension](https://docs.typo3.org/permalink/t3coreapi:publish-extension@11.5), > the extension key must be unique worldwide. This will be checked > and enforced once you register the extension key on extensions.typo3.org. > > The *extkey* is valid if the TER accepts it. This also makes sure that the > name follows the rules and is unique. > > Do this early! An already reserved key can usually only be transferred if the > original author agrees to this. 1. The *extkey* MUST be unique within your installation. 1. The *extkey* MUST be made up of lowercase alphanumeric characters and underscores only and MUST start with a letter. 1. More, see [extension key](https://docs.typo3.org/permalink/t3coreapi:extension-key@11.5) - **Examples for *extkeys*:** - `cool_shop` - `blog` Examples for names that are derived from the extkey: Here, the *extkey* is `my_extension`: - namespace: `MyVendor\MyExtension\...` - package name in `composer.json`: `vendor-name/my-extension` (the underscore is replaced by a dash) ## Vendor name {#vendor-name} The vendor name is used in: - namespaces - package name in `composer.json`, e.g. `myvendor/cool-shop` (all lowercase) > [!IMPORTANT] > The vendor name MUST be unique (if you publish your extensions > on packagist). > > Register your vendor name early on [Packagist](https://packagist.org)! Use common PHP naming conventions for vendor names in namespaces and check [PSR-0](https://www.php-fig.org/psr/psr-0/). There are currently no strict rules, but commonly used vendor names begin with a capital letter, followed by all lowercase. The vendor name (as well as the *extkey*) is spelled with all lowercase when used in the package name in the file `composer.json` For the following examples, we assume: - the vendor name is `MyCompany` - the extkey is `my_example` - **Examples:** - Namespace: `MyCompany\MyExample\...` - package name (in `composer.json`): `my-company/my-example` > [!NOTE] > **See also** > > - [PSR-0](https://www.php-fig.org/psr/psr-0/) ## Database table name {#naming-tables} These rules apply to public extensions, but should be followed nevertheless. Database table names **should** follow this pattern: ```none tx__ ``` - `` is the extension key without underscores, so `foo_bar` becomes `foobar` - `` should clearly describe the purpose of the table Examples for an extension named `cool_shop`: - `tx_coolshop_product` - `tx_coolshop_category` ### Extbase domain model tables {#naming-tables-extbase} Extbase domain model tables **should** follow this pattern: ```none tx__domain_model_ ``` - `` is the extension key without underscores, so `foo_bar` becomes `foobar` - `` should match the domain model name Examples for Extbase domain models and table names of an extension named `cool_shop`: | Domain model | Table name | | --- | --- | | `\Vendor\BlogExample\Domain\Model\Post` `\Vendor\CoolShop\Domain\Model\Tag` `\Vendor\CoolShop\Domain\Model\ProcessedOrder` `\Vendor\CoolShop\Domain\Model\Billing\Address` | `tx_blogexample_domain_model_post` `tx_coolshop_domain_model_tag` `tx_coolshop_domain_model_processedorder` `tx_coolshop_domain_model_billing_address` | > [!TIP] > You may notice, that the names above use the singular form, e.g. `post` and > not `posts`. This is recommended, but not always followed. If you do not follow this pattern, > you may need [manual mapping](https://docs.typo3.org/permalink/t3coreapi:extbase-manual-mapping@11.5). ### MM-tables for multiple-multiple relations between tables {#naming-tables-mm} **MM** tables (for multiple-multiple relations between tables) follow these rules. Extbase: ```none # rule for Extbase tx__domain_model___mm # example: EXT:blog with relation between post and comment tx_blogexample_domain_model_post_comment_mm ``` Non-Extbase tables usually use a similar rule, without the "domain_model" part: ```none # recommendation for non-Extbase third party extensions tx____mm # Example tx_myextension_address_category_mm # example for TYPO3 core: sys_category_record_mm ``` ## Database column name {#database-column-name} When extending a common table like `tt_content`, column names SHOULD follow this pattern: ```none tx__ ``` - `` is the extension key without underscores, so `foo_bar` becomes `foobar` - `` should clearly describe the purpose of the column ## Backend module key (modkey) {#backendmodulekey} The **main module key** SHOULD contain only lowercase characters. Do not use an underscore or dash. The **submodule key** MUST be made up of alphanumeric characters only. It MAY contain underscores and MUST start with a letter. - **Example:** - `Coolshop` Example usage: **EXT:my_extension/ext_tables.php** ```php // Module System > Backend Users \TYPO3\CMS\Extbase\Utility\ExtensionUtility::registerModule( // ExtensionName 'CoolShop', // Main module key (use existing main module 'web' here) 'web', // Submodule key 'ProductManagement' // ... ); ``` ## Backend module signature {#backend-module-signature} The backend module signature is a derived identifier which is constructed by TYPO3 when the module is registered. The signature is usually constructed by using the [main module key and submodule key](https://docs.typo3.org/permalink/t3coreapi:backendmodulekey@11.5), separated by an underscore. Conversions, such as underscore to UpperCamelCase or conversions to lowercase may be applied in this process. Examples (from TYPO3 core extennsions): - web_info - web_FormFormbuilder - site_redirects > [!TIP] > Registered modules are added to `$GLOBALS['TBE_MODULES']`. > > You can look at existing module signatures in > **System > Configuration > Backend Modules**. ## Plugin key {#plugin-key} The plugin key is registered in: - second parameter in `registerPlugin()` (Extbase) - or in `addPlugin()` (for non Extbase plugins) The same plugin key is then used in the following: - second parameter in `configurePlugin()` (Extbase): MUST match registered plugin key exactly - the [plugin signature](https://docs.typo3.org/permalink/t3coreapi:naming-conventions-plugin-signature@11.5) - in TypoScript, e.g. `plugin.tx_myexample_myplugin` - in TCA - etc. The plugin key can be freely chosen by the extension author, but you SHOULD follow these conventions: - do not use underscore - use UpperCamelCase, e.g. InventoryList - use alphanumeric characters For the plugin key, `Pi1`, `Pi2` etc. are often used, but it can be named differently. The plugin key used in `registerPlugin()` and `configurePlugin()` MUST match. ## Plugin signature {#naming-conventions-plugin-signature} The plugin signature is automatically created by TYPO3 from the extension key and plugin key. For this, all underscores in extension key are omitted and all characters lowercased. The extkey and plugin key are separated by an underscore (`_`): `extkey_pluginkey` The plugin signature is used in: - the database field `tt_content.list_type` - when defining a [FlexForm](https://docs.typo3.org/permalink/t3coreapi:flexforms@11.5) to be used for the plugin in `addPiFlexFormValue()` - **Examples:** Assume the following: - extkey is `my_extension` - plugin key is `InventoryList` The derived name for the "plugin signature" is: - `myextension_inventorylist` This is used in tt_content.list_type and as first parameter of `addPiFlexFormValue()`. ## Class name {#class-name} Class names SHOULD be in UpperCamelCase. - **Examples:** - `CodeCompletionController` - `AjaxController` > [!NOTE] > **See also** > > This follows [PSR-1](https://www.php-fig.org/psr/psr-1/) conventions. ## Upgrade wizard identifier {#upgrade-wizard-identifier} You SHOULD use the following naming convention for the identifier: `extKey_wizardName` This is not enforced. Please see [Wizard identifier](https://docs.typo3.org/permalink/t3coreapi:upgrade-wizards-identifier@11.5) in the Upgrade Wizard chapter for further explanations. ## Note on "old" extensions {#extension-old-extensions} Some the "classic" extensions from before the extension structure came about do not comply with these naming conventions. That is an exception made for backwards compatibility. The assignment of new keys from the TYPO3 Extension Repository will make sure that any of these old names are not accidentally reassigned to new extensions. Furthermore, some of the classic plugins (tt_board, tt_guest etc) use the "user\_" prefix for their classes as well. ## Further reading {#further-reading} > [!NOTE] > **See also** > > - [extension key](https://docs.typo3.org/permalink/t3coreapi:extension-key@11.5) > - [Publish your extension](https://docs.typo3.org/permalink/t3coreapi:publish-extension@11.5) > - [Coding guidelines](https://docs.typo3.org/permalink/t3coreapi:cgl@11.5) > - [Xliff language file id naming conventions](https://docs.typo3.org/permalink/t3coreapi:xliff-id-naming@11.5)