Xamarin is a popular framework that allows developers to create mobile applications for both iOS and Android using a single codebase. This means that instead of writing separate code for each platform, developers can write their app in C#, which is then compiled into native code for each operating system. This approach saves time and resources while ensuring a consistent user experience across devices. One of the key benefits of using Xamarin is its ability to access native APIs, enabling developers to utilize device features like the camera, GPS, and notifications. Additionally, Xamarin integrates well with other tools and services, making it a flexible choice for building high-quality mobile apps.