Difference between Windows App SDK and WinUI 3

Question

I develop many UWP apps to Windows 10, but to Windows 11 I have so many questions and sometimes the Microsoft Docs it's confusing. I want develop new apps to Windows 11 but I am totally lost!

What is the difference between Windows App SDK and WinUI 3? I dont understand :(

And what is the best way to develop Windows 11 apps? Still UWP? Or Windows App SDK? Or WinUI 3?

UWP dont have round corners thats correct? I create a new project in my computer with Windows 11 in visual Studio 2022 and only the window of my app have rounder corners, but another elements (for example buttons) dont have rounded corners!

And Mica is not only availabe in WinUI 3?

Junkman

WinUI is part of the app SDK. Reality is, UWP is dead, WinUI is the next big thing. Ironically for now you'll find most links to equivalent WinUI calls at the bottom of UWP docs for a member. – Muster

"UWP dont have round corners thats correct?" - If you are targeting the UWP you can choose to use the UI framework that ships as part of the platform. In doing so you get the clean, strong design language that made Windows 8 through 10 unique. You can also choose to use Win UI 2, and get all the fugliness like rounded corners. You can also choose the Windows App SDK and Win UI 3, and get the worst of both worlds. – Moonlit

Any updates about this issue? – Trey

"If you are targeting the UWP you can choose to use the UI framework". How can choose the UI framework? When I create a new UWP project dont have any option to choose that – Frants

You choose by selecting the components from the respective namespaces. The UI framework that ships as part of the platform is under the Windows.UI.Xaml namespace. The Win UI 2 implementation lives in the Microsoft.UI.Xaml namespace. – Moonlit

Answer 1

The Windows App SDK is the next evolution in the Windows app development platform.

WinUI is the UI part of the Windows App SDK. It provides UI features for the Windows App SDK apps. When you create a Windows app SDK app, you have to use WinUI3 to create the UI layout. The previous version of WinUI like WinUI 2.7 could be used in UWP apps.

Using UWP or Windows App SDK depends on your own requirements and scenario, both of them could work on Windows 11.

Trey