Introducing .NET Multi-platform App UI

Scott Hunter [MSFT]

You can build anything with .NET. It’s one of the main reasons millions of developers choose .NET as the platform for their careers, and companies invest for their businesses. With .NET 5 we begin our journey of unifying the .NET platform, bringing .NET Core and Mono/Xamarin together in one base class library (BCL) and toolchain (SDK).

As we consider what building device applications will look like in a unified .NET, we see many devices across multiple platforms used, from Android and iOS to Windows and macOS. To address this need we are excited to announce a new first-class UI framework for doing just that: .NET Multi-platform App UI, affectionately called .NET MAUI.

Let us introduce you to what .NET MAUI is, the single project developer experience, modern development patterns, and a look at the journey ahead.

MAUI overview

What is .NET MAUI

.NET MAUI is an evolution of the increasingly popular Xamarin.Forms toolkit that turns 6 years old this month. For years companies such as UPS, Ernst & Young, and Delta have been leveraging the mobile expertise of Xamarin atop .NET to power their businesses; some since the very beginning. It has also been very successful in helping small businesses maximize their development investment sharing upwards of 95% of their code, and beating their competitors to market. .NET MAUI extends this success on mobile to embrace the desktop making it the best way to build multi-platform applications across both, especially our new devices such as the new Surface Duo.

.NET MAUI simplifies the choices for .NET developers, providing a single stack that supports all modern workloads: Android, iOS, macOS, and Windows. The native features of each platform and UI control are within reach in a simple, cross-platform API for you to deliver no-compromise user experiences while sharing even more code than before.

Single Project Developer Experience

.NET MAUI is built with developer productivity in mind, including the project system and cross-platform tooling that developers need. .NET MAUI simplifies the project structure into a single project to target multiple platforms. This means you can easily deploy to any target that you wish including your desktop, emulators, simulators, or physical devices with a single click. With built-in cross-platform resources you will be able to add any images, fonts, or translation files into the single project, and .NET MAUI will automatically setup native hooks so you can just code. Finally, you will always have access the native underlying operating system APIs and it will be easier than ever with new platform specific integrations. Under platforms you can add source code files for a specific operating system and access the native APIs. With .NET MAUI everything is in one place where you need it to keep you productive.

.NET MAUI Single Project

This delivers:

  • One project targeting multiple platforms and devices
  • One location to manage resources such as fonts and images
  • Multi-targeting to organize your platform-specific code

You master one way to build client apps, the .NET MAUI way, and all platforms are within your reach. Today, Scott Hanselman and I will demo it in action at Build, The Journey to One .NET.

Modern App Patterns

Part of the vision for one .NET is providing developer choice in the areas of personal preferences so you can be most productive using .NET. This manifests in which IDE you use whether Visual Studio 2019, Visual Studio for Mac, or even Visual Studio Code. .NET MAUI will be available in all of those, and support both the existing MVVM and XAML patterns as well as future capabilities like Model-View-Update (MVU) with C#, or even Blazor.


Model-View-ViewModel (MVVM) and XAML, the predominant pattern and practice among .NET developers for decades now, are first-class features in .NET MAUI. This will continue to grow and evolve to help make you productive building and maintaining production apps.

    <Label Text="Welcome to .NET MAUI!" />
    <Button Text="{Binding Text}" 
            Command="{Binding ClickCommand}" />
public Command ClickCommand { get; }

public string Text { get; set; } = "Click me";

int count = 0;

void ExecuteClickCommand ()
    Text = $"You clicked {count} times.";


In addition, we are enabling developers to write fluent C# UI and implement the increasingly popular Model-View-Update (MVU) pattern. MVU promotes a one-way flow of data and state management, as well as a code-first development experience that rapidly updates the UI by applying only the changes necessary. For more information about MVU as a pattern, check out this Elm Programming guide and this blog from Thomas Bandt.

Below is a basic counter example in the MVU style written in .NET MAUI.

readonly State<int> count = 0;

View body() => new StackLayout
    new Label("Welcome to .NET MAUI!"),
    new Button(
        () => $"You clicked {count} times.",
        () => count.Value ++)

This pattern is ideally suited for hot reload as you can see below with added styling, gradients, and fonts with instant hot reload from C#.

MAUI model-view-update

Both MVVM and MVU deliver the same native applications, performance, and platform fidelity. Developers will be able to choose which style best suits their preference and use case.

Transitioning from Xamarin.Forms to .NET MAUI

Xamarin.Forms developers will hit the ground running with new projects in .NET MAUI, using all the same controls and APIs they have grown to know and love. As we get closer to the .NET MAUI launch, In order to help developers make a smooth transition of existing apps to .NET MAUI we intend to provide try-convert support and migration guides similar to what we have today for migrating to .NET Core.

The .NET MAUI Timeline

We will begin shipping .NET MAUI previews later this year, and target general availability with .NET 6 in November of 2021. .NET MAUI will ship on the same 6 week cadence that Xamarin.Forms has been on. We have published the .NET MAUI roadmap on GitHub and invite you to join us there today!

What’s Next for Xamarin and Xamarin.Forms

As part of our .NET unification, Xamarin.iOS and Xamarin.Android will become part of .NET 6 as .NET for iOS and .NET for Android. Because these bindings are projections of the SDKs shipped from Apple and Google, nothing changes there, however build tooling, target framework monikers, and runtime framework monikers will be updated to match all other .NET 6 workloads. Our commitment to keeping .NET developers up-to-date with the latest mobile SDKs is foundational to .NET MAUI and remains firm. When .NET 6 ships, we expect to ship a final release of Xamarin SDKs in their current form that will be serviced for a year. All modern work will at that time shift to .NET 6.

Xamarin.Forms will ship a new major version later this year, and continue to ship minor and service releases every 6 weeks through .NET 6 GA in November 2021. The final release of Xamarin.Forms will be serviced for a year after shipping, and all modern work will shift to .NET MAUI.

Get Involved Today

Join us on this journey to .NET MAUI at our brand new repository dotnet/maui. Be sure to star and watch to get notifications, then join in the discussion of proposals describing how we want to evolve the code base. This is the very beginning of a long journey welding Xamarin and Xamarin.Forms directly into the heart of .NET, and we are excited to do this in the open with you.


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  • Micksolidien 0

    Please consider changing your rebranding effort. There is already a cross-platform UI toolkit that has had the MAUI name for over two years under the KDE community. Anyone with two seconds and a search engine would have been able to figure this out. There are a million other names out there–do the right thing and find a new one.

  • Francisco 0

    What about Linux support?

    • David OrtinauMicrosoft employee 0

      If you’re interested in contributing or collaborating on the existing GTK# implementation, I invite you to join the conversation on GitHub.

  • chao sun 0

    Please add support for linux.

  • Vincent Wang 0

    Kind of moon in water. I’d like Flutter(92K stars) to do cross-platform dev.

  • Dominique Gratpain 0

    Hi Scott,

    The first sentence of your article is:
    “You can build everything with .NET. This is one of the main reasons why millions of developers choose .NET as the platform for their careers, and companies invest for their companies. “

    It’s true or rather, it was true until Microsoft tried to stop VB.NET. It is a shame to read that MAUI works with C # or even F # but no word on VB.
    VB.NET is a major piece of the .NET puzzle.
    No, VB.NET is not the poor relation of the family. We could do everything with VB.NET as with C#.

    Please don’t interrupt VB.NET, too many developers around the world are using it.
    Microsoft must integrate VB.NET into new developments. Do not make this error as Microsoft can do it: tiles without start button in the windows of Steve Balmer, silverlight ..

    Thank you in advance for your answer

  • Sébastien PEROT 0

    too bad button has still only a text as string, the force of wpf is contentcontrol with object si you can put a panel in button …

  • Shiraz Adam 0

    Xamarin Forms are absolute trash! Looks like I’ll be moving away from .NET because this does not sound promising to me at all.

    I’m sticking with RAD Studio for all my iOS / Windows cross platform development needs

  • Io Lo 0

    Why did you choose the name Maui? I think the people who chose that name didn’t do the job right. There’s already a project with the same name and the same functions. Except that it uses Qt and KDE frameworks: Maui

    Plus I looked it up and apparently there’s a registered trademark since 2018. Anyway, I hope at least it’s not plagiarism, because that would mean that Microsoft is so awesome that it’s fallen down… It’s a real shame.

  • Anton Plotnikov 0

    Hello. What about business applications? We use the WPF, and our customers quite often ask us about versions for macOS (more often), and Linux (hardly ever). What is your vision about the future of the WPF? Will the MAUI be able to replace it with all rich-client features like multi-window, drag-and-drop with the shell, heavy controls like grids and trees, P/Invoke, and so on?

  • Francisco González Venegas 0

    What about VB.NET support?

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