---
title: "Create your own extension"
manual: "Getting Started"
version: "13.4"
permalink: "https://docs.typo3.org/permalink/t3start:create-own-extension@13.4"
source: "Extensions/CreateOwnExtension.rst"
modified: "2026-09-15T08:44:38+00:00"
---

# Create your own extension

In TYPO3, extensions allow you to expand the system’s functionality by
adding new features and customizing behavior according to your project's needs.

## Prerequisites

-   A working [TYPO3 installation](https://docs.typo3.org/permalink/t3start:installation-ddev-tutorial@13.4)
    using Composer.
-   Familiarity with Composer
-   Basic knowledge of PHP and TYPO3 development concepts
-   CLI access to your TYPO3 instance

## Why create an extension?

Creating an extension allows you to:

-   Add custom features and modules to TYPO3
-   Share functionality across multiple TYPO3 instances

## How to start developing an extension

Developing an extension involves several steps, from setting up the extension
structure to implementing your custom functionality.
To guide you through this process, TYPO3 provides a detailed tutorial on
extension development.

Please refer to this [link](https://docs.typo3.org/m/typo3/reference-coreapi/13.4/en-us/ExtensionArchitecture/Tutorials/Index.html#extension-tutorials) for
comprehensive, step-by-step instructions on how to create an extension.

## Basic steps to create an extension

-   Define the purpose of your extension.

    Determine what specific functionality or feature you want to add to TYPO3
-   Create the extension skeleton

    Set up the basic structure for your extension.
-   Implement the desired features

    Add the necessary PHP classes, TypoScript configuration and templates
    that will bring your extension's functionality to life.
-   Register the extension in TYPO3

    Register your extension so TYPO3 can recognize it. This includes adding it
    to your instance's configuration.
-   Test and refine

    Test your extension to ensure it works as expected and make any needed
    adjustments.