# Creating a new extension¶

This chapter is not a tutorial about how to create an Extension. It only aims to be a list of steps to perform and key information to remember.

First you have to register an extension key. This is the unique identifier for your extension.

## Kickstarting the extension¶

Although it is possible to write every single line of an extension from scratch, there is a tool which makes it easier to start. It is called “Extension builder” (key: “extension_builder”) and can be installed from TER.

Hint

The extension builder in TER is usually not up to date. If you can’t find a version supporting the latest TYPO3 version in TER, you can take a look into the official github repository.

The Extension Builder comes with its own BE module:

Note that this tool is not a complete editor. It helps you to create the scaffolding of your extension and to generate all necessary PHP files. Then you can enhance these files with your own code.

Warning

The Extension Builder has the feature to preserve code, but it should still be used with care.

After the extension has been written to the folder typo3conf/ext, you will be able to activate it locally and start using it.