Flutter is a cross-platform UI toolkit that is designed to allow code reuse across operating systems such as iOS and Android, while also allowing applications to interface directly with underlying platform services. The goal is to enable developers to deliver high-performance apps that feel natural on different platforms, embracing differences where they exist while sharing as much code as possible.
During development, Flutter apps run in a VM that offers stateful hot reload of changes without needing a full recompile. For release, Flutter apps are compiled directly to machine code, whether Intel x64 or ARM instructions, or to JavaScript if targeting the web. The framework is open source, with a permissive BSD license, and has a thriving ecosystem of third-party packages that supplement the core library functionality.
This overview is divided into a number of sections:
- The layer model: The pieces from which Flutter is constructed.
- Reactive user interfaces: A core concept for Flutter user interface development.
- An introduction to widgets: The fundamental building blocks of Flutter user interfaces.
- The rendering process: How Flutter turns UI code into pixels.
- An overview of the platform embedders: The code that lets mobile and desktop OSes execute Flutter apps.
- Integrating Flutter with other code: Information about different techniques available to Flutter apps.
- Support for the web: Concluding remarks about the characteristics of Flutter in a browser environment.
