Flutter is an

open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...

software development kit A software development kit (SDK) is a collection of software development tools in one installable package. They facilitate the creation of applications by having a compiler, debugger and sometimes a software framework. They are normally specific ...

created by

Google Google LLC () is an American Multinational corporation, multinational technology company focusing on Search Engine, search engine technology, online advertising, cloud computing, software, computer software, quantum computing, e-commerce, ar ...

. It is used to develop cross-platform applications for Android,

iOS iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple Inc. exclusively for its hardware. It is the operating system that powers many of the company's mobile devices, including the iPhone; the term also include ...

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which i ...

macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac (computer), Mac computers. Within the market of ...

Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ...

Google Fuchsia Fuchsia is an open-source capability-based operating system developed by Google. In contrast to Google's Linux-based operating systems such as ChromeOS and Android, Fuchsia is based on a custom kernel named Zircon. It publicly debuted as a sel ...

, and the

web Web most often refers to: * Spider web, a silken structure created by the animal * World Wide Web or the Web, an Internet-based hypertext system Web, WEB, or the Web may also refer to: Computing * WEB, a literate programming system created b ...

from a single

codebase In software development, a codebase (or code base) is a collection of source code used to build a particular software system, application, or software component. Typically, a codebase includes only human-written source code files; thus, a codeba ...

. First described in 2015, Flutter was released in May 2017.

History

The first version of Flutter was known as "Sky" and ran on the Android

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

. It was unveiled at the 2015

Dart Dart or DART may refer to: * Dart, the equipment in the game of darts Arts, entertainment and media * Dart (comics), an Image Comics superhero * Dart, a character from ''G.I. Joe'' * Dart, a ''Thomas & Friends'' railway engine character * D ...

developer summit with the stated intent of being able to render consistently at 120

frames per second A frame is often a structural system that supports other components of a physical construction and/or steel frame that limits the construction's extent. Frame and FRAME may also refer to: Physical objects In building construction * Framing (c ...

. During the keynote of

Google Developer Day Google Developer Day events were one-day web developer-focused gatherings around the world held annually by Google. They include seminars and codelabs focused on building of web, mobile, and enterprise applications with Google and open web tec ...

s in Shanghai in September 2018, Google announced Flutter Release Preview 2, the last major release before Flutter 1.0. On December 4th of that year, Flutter 1.0 was released at the Flutter Live event, denoting the first stable version of the framework. On December 11, 2019, Flutter 1.12 was released at the Flutter Interactive event. On May 6, 2020, the Dart software development kit ( SDK) version 2.8 and Flutter 1.17.0 were released, adding support for the

Metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typi ...

API which improves performance on iOS devices by approximately 50%, as well as new Material widgets and network tracking development tools. On March 3, 2021, Google released Flutter 2 during an online Flutter Engage event. This major update brought official support for web-based applications with a new Canvas Kit renderer and web specific widgets, early-access desktop application support for

, and

and improved Add-to-App

API An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how ...

s. This release also utilized Dart 2.0 that featured sound null-safety, which caused many breaking changes and issues with many external packages; however, the Flutter team included instructions and tools to mitigate these issues. On September 8th, 2021, Dart 2.14 and Flutter 2.5 were released by Google. The update brought improvements to the Android full-screen mode and the latest version of Google's

Material Design Material Design (codenamed Quantum Paper) is a design language developed by Google in 2014. Expanding on the "cards" that debuted in Google Now, Material Design uses more grid-based layouts, responsive animations and transitions, padding, and ...

called Material You. Dart received two new updates, standardizing lint conditions and marking support for

Apple Silicon Apple silicon is a series of system on a chip (SoC) and system in a package (SiP) processors designed by Apple Inc., mainly using the ARM architecture. It is the basis of most new Mac computers as well as iPhone, iPad, iPod Touch, Apple ...

as stable. On May 12, 2022, Google announced the release of Flutter 3 and Dart 2.17. This update expanded the total number of platforms supported to six, including stable support for Linux and macOS on both Intel and Apple Silicon processors. On August 30, 2022, Flutter 3.3 was announced. This released featured

Objective-C Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. Originally developed by Brad Cox and Tom Love in the early 1980s, it was selected by NeXT for its N ...

and

Swift Swift or SWIFT most commonly refers to: * SWIFT, an international organization facilitating transactions between banks ** SWIFT code * Swift (programming language) * Swift (bird), a family of birds It may also refer to: Organizations * SWIFT ...

interop and an early preview of a new rendering engine called "Impeller" which aims to reduce stutter caused by

shader In computer graphics, a shader is a computer program that calculates the appropriate levels of light, darkness, and color during the rendering of a 3D scene - a process known as '' shading''. Shaders have evolved to perform a variety of spec ...

compilation.

Framework architecture

The major components of Flutter include: *

platform * Flutter engine * Foundation library * Design-specific widgets * Flutter Development Tools (DevTools)

Dart Language

Flutter apps are written in the

language and make use of many of the language's more advanced features. While writing and debugging an application, Flutter runs in the Dart

virtual machine In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized har ...

, which features a just-in-time execution engine. This allows for fast compilation times as well as "hot reload", with which modifications to source files can be injected into a running application. Flutter extends this further with support for

stateful In information technology and computer science, a system is described as stateful if it is designed to remember preceding events or user interactions; the remembered information is called the state of the system. The set of states a system can oc ...

hot reload, where in most cases changes to source code are reflected immediately in the running app without requiring a restart or any loss of

state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * ''The State'' (newspaper), a daily newspaper in Columbia, South Carolina, United States * '' Our ...

. For better performance, release versions of Flutter apps on all platforms use ahead-of-time (AOT) compilation, except for on the Web where code is transpiled to

JavaScript JavaScript (), often abbreviated as JS, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. As of 2022, 98% of Website, websites use JavaScript on the Client (computing), client side ...

. Flutter inherits Dart'
Pub

package manager A package manager or package-management system is a collection of software tools that automates the process of installing, upgrading, configuring, and removing computer programs for a computer in a consistent manner. A package manager deals w ...

and

software repository A software repository, or repo for short, is a storage location for software packages. Often a table of contents is also stored, along with metadata. A software repository is typically managed by source control or repository managers. Package ...

, which allows users to publish and use custom packages as well as Flutter-specific plugins.

Flutter engine

Flutter's engine, written primarily in C++, provides low-level

rendering Render, rendered, or rendering may refer to: Computing * Rendering (computer graphics), generating an image from a model by means of computer programs * Architectural rendering, creating two-dimensional images or animations showing the attributes ...

support using either Google's Skia graphics library or the custom "Impeller" graphics layer. Additionally, it interfaces with

platform-specific A platform-specific model is a model of a software or business system that is linked to a specific technological platform (e.g. a specific programming language, operating system, document file format or database). Platform-specific models are indi ...

SDKs such as those provided by Android and

iOS iOS (formerly iPhone