Flutter is an open-source UI software development kit created by Google. It is used to develop cross-platform applications for Android and iOS.
React Native is an open-source UI software framework created by Meta Platforms, Inc. It is used to develop applications for Android and iOS.
Swift is a high-level general-purpose, multi-paradigm, compiled programming language developed by Apple Inc. and the open-source community
Kotlin is a cross-platform, statically typed, general-purpose high-level programming language with type inference.