Avalonia is a cross-platform UI framework for .NET that enables developers to build desktop, mobile, embedded, and WebAssembly applications using C# and XAML.
The framework addresses the need for a single codebase that runs across Windows, macOS, Linux, iOS, Android, and WebAssembly. It accomplishes this through a flexible styling system and XAML-based declarative UI design. The README positions Avalonia as the spiritual successor to WPF, offering a familiar development experience for XAML developers while incorporating improvements over its predecessor. For teams with existing WPF applications, Avalonia XPF provides a commercial option to run WPF apps on macOS and Linux with minimal code changes.
Avalonia suits teams building cross-platform applications who want to leverage C# and XAML expertise across multiple target platforms. The framework is production-ready and used by established companies. Developers should note that while Avalonia is similar to WPF, it is not a one-to-one copy. The project provides tooling support across multiple development environments, including Visual Studio Code with a dedicated extension offering XAML previewing and code completion, Visual Studio 2022 and 2026 with project templates and live XAML preview, and JetBrains Rider.
The project maintains active development with regular updates to its documentation and tooling ecosystem. Development is supported through sponsorship, which sustains ongoing work on the framework and its supporting infrastructure.