maui

dotnet/maui is the source code for .NET MAUI (Multi-platform App UI), Microsoft's framework for building native mobile and desktop applications from a single shared codebase. Instead of writing separate apps for iPhone, Android, Windows, and Mac, you write one app in C# and XAML (a markup language for describing user interfaces) and MAUI compiles it to run natively on each platform.

The key benefit is code reuse: business logic, data handling, and much of the user interface can be shared across all target platforms, while still producing apps that feel native and use the platform's own controls and capabilities. It is the successor to Xamarin.Forms, expanding beyond mobile to also cover Windows and macOS desktop apps.

You would use .NET MAUI when you're building a cross-platform app and your team already works in the .NET ecosystem (C#, Visual Studio), or when you need to ship to both mobile and desktop without maintaining separate codebases. It integrates with Visual Studio and includes emulators for testing on Android and iOS without physical devices.

The framework targets Android, iOS, iPadOS, macOS (via Mac Catalyst), and Windows. You create a new project with a single command, and it sets up the shared structure automatically. It is written in C# and is an official Microsoft open-source project.