Flutter is an open-source software development kit which enables smooth and easy cross-platform mobile app development. You can build high quality natively compiled apps for iOS and Android quickly, without having to write the code for the two apps separately. All you need is one codebase for both platforms.
React Native lets you create truly native apps and doesn't compromise your users' experiences. It provides a core set of platform agnostic native components like View , Text , and Image that map directly to the platform's native UI building blocks.
React Native is an open-source mobile application framework created by Facebook. It is used to develop applications for Android, iOS, Web and UWP (Windows) providing native UI controls and full access to the native platform. Working with React Native requires an understanding of JavaScript fundamentals.
Xamarin is an open-source platform for building modern and performant applications for iOS, Android, and Windows with . NET. Xamarin is an abstraction layer that manages communication of shared code with underlying platform code.
Xamarin allows code reusability where developers have to make code once and share it to iOS and Android. Xamarin also offers complete access to native APIs and tools used across Android, iOS, and Windows platforms. So, it can deliver nearly native design and performance-driven applications.