Flutter apps are written using the Dart programming language, also originally from Google and now an ECMA standard. Dart shares many of the same features as other modern languages such as Kotlin and Swift, and can be transcompiled into JavaScript code.
As a cross-platform framework, Flutter most closely resembles React Native, as Flutter allows for a reactive and declarative style of programming. Unlike React Native, however, Flutter does not need to use a Javascript bridge, which can improve app startup times and overall performance. Dart achieves this by using Ahead-Of-Time or AOT compilation.
Another unique aspect of Dart is that it can also use Just-In-Time or JIT compilation. JIT compilation with Flutter improves the development workflow by allowing hot reload capability to refresh the UI during development without the need for an entirely new build.
As you’ll see in this tutorial, the Flutter framework is heavily built around the idea of widgets. In Flutter, widgets are not used just for the views of your app, but also for entire screens and even for the app itself.