The SWF file format (Flash) doesn't provide any system functions, such as launching external applications, opening external documents, creating new directories, text file reading and writing, displaying the common dialogs, etc. SWFKit extends the power of Flash, you can call system functions from within SWF files.

Generally, the extended functions are provided by fscommands. After the Flash MX has come out, fscommands can be wrapped in components and be called implicitly in Action Script. The latter method is better than the former. For coding with components is more clear than coding with fscommands. But both methods have many limitations. Considering the limitations, SWFKit provides a different way to extend the power of Flash – the FFish scripting language.