Is Flutter frontend or backend?

Flutter uses the Dart programming language, a modern, object-oriented language created by Google. Through its support for native and web development, as well as its use of powerful tools like the Flutter SDK, App Engine, and Firebase, Dart makes it easy to quickly build high-quality mobile apps with Flutter.
Flutter is made as a cross-platform SDK that can be used to build frontend and backend applications in a variety of programming languages, including Dart, Java, C/C++, and more. Its powerful framework and tools make it easy to quickly build high-quality mobile apps for any purpose.