A cross platform development environment that lets you build native apps for iOS, Mac and other platforms in C#. Xamarin lets you write C# that can be shared across all the platforms it supports but uses native UIs for each platform to give the best user experience. Xamarin includes a complete IDE, Xamarin Studio for Mac and Windows, or you can use Xamarin with Visual Studio. They also offer other features to allow you to utilise over 20,000 .NET libraries and to test your app on hundreds of real devices in their Test Cloud.