Swift vs Xamarin: What are the differences?
Swift: An innovative new programming language for Cocoa and Cocoa Touch. Writing code is interactive and fun, the syntax is concise yet expressive, and apps run lightning-fast. Swift is ready for your next iOS and OS X project — or for addition into your current app — because Swift code works side-by-side with Objective-C; Xamarin: Create iOS, Android and Mac apps in C#. Xamarin’s Mono-based products enable .NET developers to use their existing code, libraries and tools (including Visual Studio*), as well as skills in .NET and the C# programming language, to create mobile applications for the industry’s most widely-used mobile devices, including Android-based smartphones and tablets, iPhone, iPad and iPod Touch.
Swift belongs to "Languages" category of the tech stack, while Xamarin can be primarily classified under "Cross-Platform Mobile Development".
"Ios", "Elegant" and "Not Objective-C" are the key factors why developers consider Swift; whereas "Power of c# on mobile devices", "Native apps with native ui controls" and "Native performance" are the primary reasons why Xamarin is favored.
Swift is an open source tool with 48.2K GitHub stars and 7.71K GitHub forks. Here's a link to Swift's open source repository on GitHub.
According to the StackShare community, Swift has a broader approval, being mentioned in 979 company stacks & 526 developers stacks; compared to Xamarin, which is listed in 74 company stacks and 65 developer stacks.