An SWF file is an animation created with Adobe Flash that can be played by Flash Player or with a web browser that has the Flash plugin installed. It may contain text, vector and raster graphics, and interactive content written in ActionScript.

SWF files were commonly used to bring animated graphics, video, and sound to the web in the 2000s and 2010s. They were also a popular means of delivering browser-based games. However, as web technologies improved, Flash became increasingly criticized for its shortcomings, which included performance and security issues. Adobe and many web browser developers announced that they were officially ending support for Flash at the conclusion of 2020. SWF (pronounced "Swiff") was originally an acronym for "Shockwave Flash" since the SWF format was designed for Shockwave Player. However, as SWF files became a standard means of publishing Flash content on the web, the acronym has been modified to mean Small Web Format as well. Because SWF files contain compiled ActionScript and compressed media, they are not meant to be edited. To modify a Flash animation, it is recommended to edit the original .FLA file instead. NOTE: Flash was originally developed by Macromedia, which was acquired by Adobe Systems in 2005.