'''Windows Runtime XAML Framework''' (also known as '''Windows UI LibaryLibrary''' or '''WinUI'''; WinUI2 was codenamed "Jupiter",<ref>{{cite web | url=http://blog.jerrynixon.com/2012/06/windows-8-15-more-reasons-why-i-choose.html | title=Windows 8: 15 More Reasons why I choose XAML over HTML5 | author=Jerry Nixon | date=20 June 2012 | work=Microsoft}}</ref><ref>{{cite web | url=http://blog.jerrynixon.com/2013/01/devradio-xaml-and-windows-8-app.html?spref=tw | title=DevRadio: XAML and Windows 8 App Development | author=Jerry Nixon, Tim Heuer | date=24 January 2013 | work=Microsoft}}</ref> also known as UWP XAML or simply 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 (design language)|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.
The XAML Framework is one of the multiple UI frameworks provided built-in for the Windows Runtime; the others being [[HTML5]] (e.g., via [[WinJS]]) and [[DirectX]].
