Microsoft Introduces Reactor to Build Windows 11 Apps Without XAML

Microsoft is experimenting with Microsoft.UI.Reactor, a new C# framework that lets developers build native Windows 11 applications without writing XAML.

The framework aims to simplify Windows app development, particularly for developers familiar with React, React Native, SwiftUI, and Jetpack Compose.

Microsoft wants to simplify native Windows app development

Microsoft.UI.Reactor builds on top of WinUI and uses existing Windows interface controls rather than introducing a separate rendering engine.

Traditional WinUI development requires developers to work with both XAML for interface design and C# for application logic. Reactor allows them to describe the entire interface directly in C#, reducing the need to manage multiple files and learn another language.

Microsoft believes this approach could encourage developers from other platforms to create native Windows applications instead of relying on web technologies.

However, Reactor does not replace WinUI or XAML. Microsoft confirmed that XAML remains an actively supported part of its Windows development ecosystem.

Reactor reduces code complexity and includes over 60 checks

Microsoft demonstrated how developers can recreate a sample WinUI application that normally requires five files and a project file using just a single C# file with Reactor.

The framework also includes more than 60 built-in code checks that help developers identify potential accessibility and performance problems.

Another feature allows applications to preserve their state across most code changes. This means developers can update interfaces and see the results without repeatedly restarting their applications.

Reactor’s C#-first approach could also simplify development with AI coding assistants, which can generate and modify interface code without switching between C# and XAML.

Microsoft hopes to attract more native Windows 11 developers

Microsoft’s experiment reflects its efforts to make native Windows development more accessible, particularly to developers who currently prefer web-based applications or WebView2 wrappers.

By reducing the complexity of WinUI development, Reactor could make building native Windows 11 apps more appealing to developers working across multiple platforms.

For now, Microsoft.UI.Reactor remains experimental, and Microsoft has not announced a timeline for general availability.

Meanwhile, Microsoft has also made changes elsewhere, including ending its Garage program and shutting down 15 workspaces. On the gaming side, the company is expanding Advanced Shader Delivery to all major GPUs.