Developers can create Extensions to add new layouts, modules, file system providers, scheduled tasks, content editors, entire line-of-business applications and other components. Extensions are .NET core class libraries, typically developed in Visual Studio and C#.
Extensions are packaged as zip files with a manifest (package.xml file) and are installed by site administrators.
The extensions system in Nucleus CMS uses .NET core features to automatically isolate extension assemblies, so that different extensions can use their own private set of dependency assemblies - so different extensions can use different versions of the same package.
Nucleus CMS provides developer tools (Visual Studio project and item templates) and framework (API) documentation so that .NET core developers can extend the application. You can download developer tools from the downloads page.
An extension can contain any combination of modules, scheduled tasks, layouts, containers or other code in a single installation package. An extension package is a zip file which contains all of the files needed for your extension, along with a manifest (package.xml) file with instructions on how to install your components.