Free. Cross-platform. Open source. An app platform for building Android and iOS apps with .NET and C#.
Xamarin extends the .NET developer platform with tools and libraries specifically for building apps for Android, iOS, tvOS, watchOS, macOS, and Windows.
Microsoft acquired Xamarin, a leading platform provider for mobile app development, in February 2016 to be included in their broader portfolio. Microsoft had a longstanding partnership with Xamarin, and has jointly built Xamarin integration into Visual Studio, Microsoft Azure, Office 365 and the Enterprise Mobility Suite to provide developers with an end-to-end workflow for native, secure apps across platforms. Xamarin has more than 15,000 customers in 120 countries, including more than one hundred Fortune 500 companies – and more than 1.3 million unique developers have taken advantage of their offering. Top enterprises such as Alaska Airlines, Coca-Cola Bottling, Thermo Fisher, Honeywell and JetBlue use Xamarin, as do gaming companies like SuperGiant Games and Gummy Drop. Through Xamarin Test Cloud, all types of mobile developers—C#, Objective-C, Java and hybrid app builders —can also test and improve the quality of apps using thousands of cloud-hosted phones and devices. Xamarin was recently named one of the top startups that help run the Internet.