Creating a new extension

First choose a unique Composer name for your extension. Additionally, an extension key is required.

If you plan to ever publish your extension in the TYPO3 Extension Repository (TER), register an extension key.

Kickstarting the extension

There are different options to kickstart an extension. You can create it from scratch or follow one of our tutorials on kickstarting an extension.

Installing the newly created extension

Starting with TYPO3 v11 it is no longer possible to install extensions in TYPO3 without using Composer in Composer-based installations.

However during development it is likely that you will want to test your extension locally before publishing it.

During development, place the extension in a directory called, packages in TYPO3s root directory. You can name is directory however you choose.

Then edit your projects composer.json (The one in the TYPO3 root directory, not the one in the extension) and add the following repository:

composer.json

{
   "repositories": [
      {
         "type": "path",
         "url": "packages/*"
      }
   ]
}

After that you can install your extension via Composer:

composer req vendor/my-extension:"@dev"

Hint

Starting with TYPO3 v11.5 all extensions installed via Composer are automatically activated when they are installed. If you use an older version of TYPO3 you will have to activate the extension in Admin Tools > Extension Manager.

For legacy installations you can put the extension directly in the directory typo3conf/ext and then activate it in Admin Tools > Extension Manager.