Windows UI Library
Windows UI Library (WinUI codenamed "Jupiter", and also known as UWP XAML and WinRT XAML) is a user interface API that is part of the Windows Runtime programming model that forms the backbone of Universal Windows Platform apps (formerly known as Metro-style or Immersive) for the Windows 8, Windows 8.1, Windows 10 and Windows Phone 8.1 operating systems. It enables declaring user interfaces using Extensible Application Markup Language (XAML) technology.
| Other names | WinUI, UWP XAML, WinRT XAML |
|---|---|
| Developer(s) | Microsoft |
| Initial release | September 2011 |
| Stable release | 2.8.2
/ January 4, 2023 |
| Preview release | 2.8.2-prerelease.220830001
/ September 1, 2022 |
| Repository | |
| Written in | C++ |
| Operating system | Microsoft Windows |
| Platform | Intel x86 32-bit, x86-64 and ARM |
| Type | Application framework |
| License | MIT License after 2018-12-04; Freeware before |
| Website | microsoft |
WinUI is one of the multiple UI frameworks provided built-in for the Windows Runtime; the others being HTML5 (e.g., via WinJS) and DirectX.
WinUI 2 is an extension library for UWP XAML containing controls and styling that match the Windows 11 design language. It is shipped through NuGet and is distinct from the UWP XAML framework, which provides the actual rendering engine; though, they may be treated synonyms.
WinUI 3 decouples WinRT XAML from the operating system as a separate package to be updated quickly and make new features work on older versions of Windows. It is part of Windows App SDK (codenamed "Project Reunion"), a Microsoft effort to reconcile the Windows desktop (Win32) and the UWP low IL app model.