Windows UI Library in the Windows App SDK (WinUI 3)

WinUI 3 is the native UI platform component that ships with the Windows App SDK (completely decoupled from Windows SDKs). The Windows App SDK provides a unified set of APIs and tools that can be used to create production desktop apps that target Windows 10 and later, and can be published to the Microsoft Store.


The Windows App SDK was previously known as Project Reunion. Some assets, such as the VSIX extension and NuGet packages, still use this code name (these will be renamed in a future release).

Windows App SDK is used in all documentation except where a specific release or asset still refers to Project Reunion.

WinUI resources

Release notes: For more details on WinUI 3 in the Windows App SDK, see WinUI 3 in the Stable channel release notes for the Windows App SDK

Github: WinUI is hosted on Github. Use the WinUI repo, to file feature requests or bugs, and interact with the WinUI team.



For more info, design guidance, and code examples, see Design and code Windows apps.

The WinUI 3 Gallery and WinUI 2 Gallery apps include interactive examples of most WinUI 3 and WinUI 2 controls, features, and functionality.

If installed already, open them by clicking the following links: WinUI 3 Gallery or WinUI 2 Gallery.

If they are not installed, you can download the WinUI 3 Gallery and the WinUI 2 Gallery from the Microsoft Store.

You can also get the source code for both from GitHub (use the main branch for WinUI 3 and the winui2 branch for WinUI 2).

See also