# 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 or from the official GitHub repository.

Attention

For TYPO3 10 you must retrieve the extension from the v10-compatibility branch from GitHub.

The Extension builder comes with its own BE module:

Note that this tool is not a complete editor. It helps you creating the scaffolding of your extension, generating the necessary files. It’s then up to you to fill these with the relevant code.

Warning

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

After the extension is written to your computer’s disk you will be able to install it locally and start using it.