SWF is an Adobe Flash file format used for multimedia, vector graphics and ActionScript. SWF files deliver graphics (including text, such as subtitles and closed captioning) and animation over the Internet. The SWF file format was designed as a very efficient delivery format and not as a format for exchanging graphics between graphics editors. SWF originated with FutureWave Software, transferred to Macromedia, and then came under the control of Adobe. Originally, the term SWF was used as an abbreviation for ShockWave Flash. SWF files are stored in files with the extension .swf.

SWF format is primarily intended for on-screen display and so it supports anti-aliasing, fast rendering to a bitmap of any color format, animation and interactive buttons. SWF is a tagged format, so the format can be evolved with new features while maintaining backwards compatibility with older players, making possible convenient file-sharing for uses such as reference, archiving and transcription. SWF files can be delivered over a network with limited and unpredictable bandwidth. SWF files are compressed to be small and support incremental rendering through streaming. Files can be displayed without any dependence on external resources such as fonts.

SWF files can be generated from within several Adobe products including Flash, Flash Builder and After Effects as well as through MXMLC, a command line application compiler which is part of the freely available Flex SDK. Although Adobe Illustrator can generate SWF format files through its export function, it cannot open or edit them. SWF files can be built with open source Motion-Twin ActionScript 2 Compiler (MTASC), the open source Ming library and the free software suite SWFT tools as well as various third party programs.

The company Future Wave Software originally defined the file format with the objective to create small files for displaying entertaining animations. The idea involved a format which player software could run on any system and which would work with slower network connections. FutureWave released FutureSplash Animator in May 1996. When Macromedia acquired FutureWave, FutureSplash Animator became Macromedia Flash and later SWF when Adobe acquired Macromedia.

Adobe makes available plugins such as Adobe Flash Player and Adobe Integrated Runtime to play SWF files in web browsers on many desktop operating systems including Microsoft Windows, Mac OS X and Linux.

Adobe has incorporated SWF playback and authoring in other product and technologies of theirs, including in Adobe Shockwave, which renders more complex documents. SWF can also be embedded in PDF files which are viewable with Adobe Reader 9 or later.

Sony PlayStation Portable consoles can play limited SWF files in Sony’s web browser, beginning with firmware version 2.71. The Nintendo Wii and the Sony PS3 consoles can run SWF files through their Internet browsers.