Visual Studio App Center vs Xamarin: What are the differences?

Visual Studio App Center: Continuous everything – Build, Tes, Deploy, Engage, Repeat. Automate the lifecycle of your iOS, Android, Windows, and macOS apps. Connect your repo and within minutes build in the cloud, test on thousands of real devices, distribute to beta testers and app stores, and monitor real-world usage with crash and analytics data. All in one place; 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.

Visual Studio App Center belongs to "Continuous Integration" category of the tech stack, while Xamarin can be primarily classified under "Cross-Platform Mobile Development".

Some of the features offered by Visual Studio App Center are:

• Build
• Test
• Distribute

On the other hand, Xamarin provides the following key features:

• Cross-platform development- Thinking about supporting iOS, Android, Mac and Windows? Xamarin allows you to write it all in C#.
• Reuse existing code- Use your favorite .NET libraries in Xamarin apps. Easily use third-party native libraries and frameworks.
• Discover as you type- Explore APIs as you type with code autocompletion.

Olo, Crowdkeep, and GoFormz are some of the popular companies that use Xamarin, whereas Visual Studio App Center is used by Partipost, Lykon GmbH, and BeachBody. Xamarin has a broader approval, being mentioned in 105 company stacks & 432 developers stacks; compared to Visual Studio App Center, which is listed in 4 company stacks and 4 developer stacks.