---
title: Extending Silverstripe CMS
summary: Understand the ways to modify the built-in functionality through Extensions, Subclassing and Dependency Injection.
introduction: Silverstripe CMS is easily extensible to meet custom application requirements. This guide covers the wide range of API's to modify built-in functionality and make your own code easily extensible.
icon: code
---

No two applications are ever going to be the same and Silverstripe CMS is built with this in mind. The core framework 
includes common functionality and default behaviors easily complemented with add-ons such as modules, widgets and 
themes. 

Silverstripe CMS includes a myriad of extension API's such as *Extension Hooks* and support for programming patterns 
such as *Dependency Injection*. Allowing developers to tailor the framework to their needs without modifying the core 
framework.

[CHILDREN Exclude="How_Tos"]

## How to's

[CHILDREN Folder="How_Tos"]