Free. Cross-platform. Open source. An app platform for building Android and iOS apps with .NET and C#. Use .NET and C# to create native apps for the billions of Android, iPhone, iPad, Mac, and Windows devices around the world. Add to that sharing code with any .NET app, empowering you to be more productive and build apps faster than ever across all platforms. Ready to take code sharing to the next level? Xamarin.Forms is an open source mobile UI framework from Microsoft for building iOS, Android, & Windows apps with .NET from a single shared codebase. Whether you want a consistent look across platforms or prefer native look and feel, Xamarin.Forms will get you up and running in no time. .NET is a developer platform made up of tools, programming languages, and libraries for building many different types of applications. Xamarin extends the .NET developer platform with tools and libraries specifically for building apps for Android, iOS, tvOS, watchOS, macOS, and Windows.