In order to provide users (i.e. developers) with a clear abstraction, Shopware consists of a core which designed in a way that allows for a lot of extensibility without sacrificing maintainability or structural integrity. Some of those concepts were already introduced in the Frameworks section. However, the main domain for extensions (that leverage those very concepts) are Apps and Plugins. The following section will discuss what they can be used for.
Refer to our Guides section to learn how to use both extension systems, and also how they differ: