ReactiveUI is a composable, cross-platform model-view-viewmodel framework for .NET platforms that applies functional reactive programming principles to abstract mutable state from user interfaces.
The framework addresses the challenge of managing complex application state and UI synchronization by enabling developers to express feature logic in a single, readable location using reactive patterns. It leverages functional reactive programming to decouple state management from presentation, making applications easier to reason about and test. The approach centers on composable reactive streams that automatically propagate state changes through the UI layer.
Developers should adopt ReactiveUI when building applications that benefit from declarative, testable state management across multiple .NET platforms. The framework suits projects targeting WPF, WinForms, WinUI, MAUI, Xamarin, Avalonia, Blazor, Android, iOS, and other .NET platforms. It includes platform-specific packages for each target, along with dedicated testing utilities and validation extensions. The framework ships in two interchangeable distributions built on the same core engine, differing only in which reactive interop types appear in the public API, allowing developers to choose based on their dependency preferences without rewriting code.
The project maintains active engagement with its community through documentation, sample applications, and discussion channels. Development activity shows consistent attention to cross-platform support, with platform-specific packages regularly maintained alongside the core framework. The codebase includes source generators for code generation tasks and dedicated testing packages, indicating ongoing investment in developer experience and tooling. Documentation covers scheduler usage and integration patterns, reflecting practical focus on real-world adoption challenges.
