SWF (/ˈswɪf/ swif)^[2] is an abbreviation for small web format, an Adobe Flash file format used for multimedia, vector graphics and ActionScript.^[3] Originating with FutureWave Software, then transferred to Macromedia, and then coming under the control of Adobe, SWF files can contain animations or applets of varying degrees of interactivity and function. It may also be used for programs, commonly browser games, using ActionScript.

SWF files can be generated from within several Adobe products including Flash, Flash Builder (an IDE) 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. Other than Adobe products, SWFs can be built with open source Motion-Twin ActionScript 2 Compiler (MTASC), the open sourceMing library and the free software suite SWFTools. There are also various third party programs that can produce files in this format, such as Multimedia Fusion 2, Captivate and SWiSH Max.

Originally, the term SWF was used as an abbreviation for ShockWave Flash.^[4] This usage was changed to thebackronym Small Web Format to eliminate confusion with a different technology, Shockwave, from which SWF was derived.^[5][6]