Welcome to the MEF Community Site

Important: this site hosts source code for unsupported, pre-release versions of MEF. If you want to use MEF in production, you should strongly consider using the supported versions included in the .NET Framework and Silverlight.

.NET 4.5 and Windows 8 Store apps can now install the fully-supported, lightweight Microsoft.Composition package from NuGet.

What is it?

The Managed Extensibility Framework (MEF) is a composition layer for .NET that improves the flexibility, maintainability and testability of large applications. MEF can be used for third-party plugin extensibility, or it can bring the benefits of a loosely-coupled plugin-like architecture to regular applications.


MEF is a part of the Microsoft .NET Framework, with types primarily under the System.ComponentModel.Composition.* namespaces.
  • MEF has shipped with .NET 4.0 and Silverlight 4
  • MEF 2 is under development

Last edited Oct 18, 2012 at 6:15 PM by alokshriram, version 91