What is ReactiveUI?

ReactiveUI is a composable, cross-platform model-view-viewmodel framework for all .NET platforms that is inspired by functional reactive programming, which is a paradigm that allows you to abstract mutable state away from your user interfaces and express the idea around a feature in one readable place and improve the testability of your application.

🔨 Get Started 🛍 Install Packages 🎞 Watch Videos 🎓 View Samples 🎤 Discuss ReactiveUI

Documentation

• RxSchedulers - Using ReactiveUI schedulers without RequiresUnreferencedCode attributes

Book

There has been an excellent book written by our Alumni maintainer Kent Boogart.

NuGet Packages

Install the following packages to start building your own ReactiveUI app. Note: some of the platform-specific packages are required. This means your app won't perform as expected until you install the packages properly. See the Installation docs page for more info.

Platform	ReactiveUI Package	NuGet
.NET Standard	ReactiveUI
Any	ReactiveUI.SourceGenerators
Unit Testing	ReactiveUI.Testing
WPF	ReactiveUI.WPF
WinUI	ReactiveUI.WinUI
MAUI	ReactiveUI.Maui
Windows Forms	ReactiveUI.WinForms
AndroidX	ReactiveUI.AndroidX
Blazor	ReactiveUI.Blazor
Platform Uno	ReactiveUI.Uno
Platform Uno	ReactiveUI.Uno.WinUI
Avalonia	ReactiveUI.Avalonia
Any	ReactiveUI.Validation
Any	ReactiveUI.Extensions

Choosing a distribution: ReactiveUI.Primitives or System.Reactive

ReactiveUI ships in two interchangeable distributions with an identical public API, both built on the same ReactiveUI.Primitives engine and the same high-performance custom schedulers/sinks. The only difference is which reactive interop types appear in the public API — so you pick a distribution, you don't rewrite code:

You want…	Reference these packages	Public reactive types
The new, lighter default (no System.Reactive dependency)	ReactiveUI, ReactiveUI.Wpf, ReactiveUI.WinForms, ReactiveUI.WinUI, ReactiveUI.Maui, ReactiveUI.Blazor, ReactiveUI.AndroidX, …	ReactiveUI.Primitives — RxVoid, ISequencer, Signal<T>
Drop-in interop with existing System.Reactive code	ReactiveUI.Reactive, ReactiveUI.Wpf.Reactive, ReactiveUI.WinForms.Reactive, ReactiveUI.WinUI.Reactive, ReactiveUI.Maui.Reactive, ReactiveUI.Blazor.Reactive, …	System.Reactive — Unit, IScheduler

The .Reactive family is not "old ReactiveUI" — it runs on the exact same Primitives engine and custom schedulers as the default and simply surfaces System.Reactive.Unit/IScheduler (and Subject<T>) so it composes with code that already uses System.Reactive.

The default distribution drops the System.Reactive dependency for a smaller closure and a better trimming/AOT story, and is markedly faster on the hottest MVVM paths — in representative micro-benchmarks roughly 3–4× faster on WhenAnyValue/ToProperty subscribe and emit, with 5–13× less allocation (for example WhenAnyValue emit drops from ~6.8 MB to ~0.5 MB per run, and ToProperty construction from ~7.3 µs to ~1.0 µs). The fast schedulers now live in ReactiveUI.Primitives and back both distributions.

If you take the default packages, note the public reactive types change: IScheduler → ISequencer, System.Reactive.Unit → RxVoid, and Subject<T>/BehaviorSubject<T> → Signal<T>/BehaviorSignal<T>. To upgrade with zero source changes, reference the matching *.Reactive packages instead — they keep IScheduler, Unit and Subject<T>.

Core routing (RoutingState, IScreen, RoutedViewHost) stays in the main package, but the DynamicData change-set routing/collection/auto-persist helpers now live in a separate ReactiveUI.Routing package (ReactiveUI.Routing.Reactive for the System.Reactive flavor), so core no longer depends on DynamicData. Add ReactiveUI.Routing if you use those extensions.

Sponsorship

The core team members, ReactiveUI contributors and contributors in the ecosystem do this open-source work in their free time. If you use ReactiveUI, a serious task, and you'd like us to invest more time on it, please donate. This project increases your income/productivity too. It makes development and applications faster and it reduces the required bandwidth.

Become a sponsor.

Migration from Xamarin and .NET 8 MAUI

Xamarin Users

As of May 2024, Microsoft ended support for Xamarin per their support policy. ReactiveUI has removed support for legacy Xamarin platforms in favor of modern .NET MAUI. For Xamarin projects:

• Xamarin.Forms → Migrate to MAUI and use ReactiveUI.Maui
• Xamarin.Android → Migrate to MAUI Android or use ReactiveUI.AndroidX for native Android
• Xamarin.iOS/Mac → Migrate to MAUI iOS/Mac Catalyst

For guidance on migrating from Xamarin to MAUI, see the official migration documentation.

MAUI Users

ReactiveUI supports .NET 9 and .NET 10 for MAUI platforms:

• net10.0-android / net9.0-android
• net10.0-ios / net9.0-ios
• net10.0-maccatalyst / net9.0-maccatalyst
• net10.0-windows10.0.19041.0 / net9.0-windows10.0.19041.0

Non-MAUI net8.0 library targets remain fully supported.

Examples

Platform-specific sample applications are included in src/examples/:

Sample	Platform	Description
ReactiveUI.Samples.Wpf	WPF	Login form with reactive bindings, PasswordBox event marshaling
ReactiveUI.Samples.Winforms	WinForms	Login form with IViewFor, programmatic UI layout
ReactiveUI.Samples.Maui	MAUI	Cross-platform login with Shell navigation, ReactiveContentPage
ReactiveUI.Builder.WpfApp	WPF	Multi-instance chat app with routing, suspension, and network sync
ReactiveUI.Builder.BlazorServer	Blazor Server	Chat app with server-side Blazor and reactive components

All samples target .NET 10, use RxAppBuilder for initialization, and demonstrate WhenActivated, Bind/ BindCommand, and proper subscription disposal.

This is how we use the donations:

• Allow the core team to work on ReactiveUI
• Thank contributors if they invested a large amount of time in contributing
• Support projects in the ecosystem

Support

If you have a question, please see if any discussions in our GitHub issues or Stack Overflow have already answered it.

If you want to discuss something or just need help, here is our Slack room, where there are always individuals looking to help out!

Please do not open GitHub issues for support requests.

Contribute

ReactiveUI is developed under an OSI-approved open source license, making it freely usable and distributable, even for commercial use.

If you want to submit pull requests please first open a GitHub issue to discuss. We are first time PR contributors friendly.

See Contribution Guidelines for further information how to contribute changes.

Core Team

Glenn Watson Melbourne, Australia	Chris Pulman United Kingdom
Rodney Littles II Texas, USA	Colt Bauman South Korea

Alumni Core Team

The following have been core team members in the past.

Geoffrey Huntley Sydney, Australia	Kent Boogaart Brisbane, Australia	Olly Levett London, United Kingdom
Anaïs Betts San Francisco, USA	Brendan Forster Melbourne, Australia	Claire Novotny New York, USA
Artyom Gorchakov Moscow, Russia

.NET Foundation

ReactiveUI is part of the .NET Foundation. Other projects that are associated with the foundation include the Microsoft .NET Compiler Platform ("Roslyn") as well as the Microsoft ASP.NET family of projects, and Microsoft .NET Core.