Flutter is an open-source mobile app SDK created by Google. Flutter allows you to build an app using a single codebase that can be compiled to both Android and IOS. It is also used to build applications for Google Fuchsia OS.
You write your Flutter applications using a programming language called Dart. Unlike other solutions which uses a bridge, your Dart code gets compiled to machine code. This gives you the advantage of having native performance for your app.
Here’s a growing list of flutter resources I have found online: