Flutter is Google’s UI toolkit for building beautiful, natively compiled applications for mobile, web, and desktop from a single codebase. Flutter was originally launched with support for iOS and Android. Flutter 2 was launched as a stable release in March 2021, with support for Windows, macOS, Linux, and web. Flutter runs with Dart, a programming language developed by Google. Dart is a strongly-typed, object-oriented language with a familiar C-style syntax. Developers can compile Dart programs into fast native code that runs smoothly on all supported platforms. On the web, Dart is compiled to JavaScript code that can run on the browser. Flutter is composed of three architectural layers: the Flutter framework, which is written in Dart and provides all the widgets that developers use to build their apps; the Flutter Engine, written in C++, which provides low-level rendering support with Google’s Skia; and the platform-specific Embedder, which talks directly to the operating system.

Flutter, first known as “Sky”, was announced in 2015 with Android support only. It was created to provide a better mobile experience for users and developers, taking the best parts of the web development experience, and bringing them to mobile. Its main goals were high-performance and portability across multiple platforms. While other cross-platform solutions such as React Native and Xamarin were already popular, they could not deliver the same fidelity and performance as apps built with the native iOS and Android SDKs. Flutter changed that by making it possible to create beautiful, performant apps across multiple platforms with a single codebase.

Flutter has been a production-ready, stable product on iOS and Android since its official launch in December 2018. Big companies such as eBay, BMW, Alibaba, and Toyota are using Flutter as the core framework for their mobile app development strategy. Over a hundred thousand Flutter apps have already been published on the App Store and Play Store. After overtaking React Native in Google Search trends, Flutter is now the fastest growing software project on GitHub. By choosing Flutter, companies can deliver mobile apps in record-time as they no longer have to build separate apps to support iOS and Android. This makes Flutter an ideal choice for startups, agencies, and small businesses, and as a result, the job market for Flutter developers is also expanding rapidly.