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File Format
Name SWF
Extension(s) .swf, .spl
MIME Type(s) application/vnd.adobe.flash.movie, application/x-shockwave-flash, application/futuresplash
LoCFDD fdd000248, others
PRONOM fmt/507, others
Wikidata ID Q594447, or lots of others for specific versions
Kaitai Struct Spec swf.ksy
Released 1996

Adobe Flash (or Macromedia Flash, Shockwave Flash, FutureSplash) is a platform for multimedia applications. SWF (Small Web Format, or Shockwave Flash) is its format for Flash applications that can be run in the browser. Fundamentally it is an animated vector graphics format, but it has many other features, and can contain complete computer programs written in ActionScript. Among its common uses are advertisements, web site user interfaces, video games and other applets, and video playback.

SWF is not designed to be editable. Instead, SWF files are usually compiled from a source (project) format called FLA. The ActionScript programming language is also used.

Flash was at the height of popularity for interactive browser applications in the 2000's, but notoriously suffered from security vulnerabilities (and continues to do so as of this writing). It was also dealt a serious blow when Apple decided not to support it in iOS devices, and Web developers have generally turned to HTML 5 as a replacement. In July 2017, in perhaps the first Flash update anyone has cared for, Adobe announced that Flash will reach its end-of-life in 2020.

The SWF format is only currently useful for building Adobe AIR applications and games. Adobe AIR is a somewhat popular (although lesser known) framework for developing cross-platform apps/games. It is used to build Angry Birds and a couple of other games.

The Adobe Animate program is one of the programs from Adobe which works with this format, but it is also one of the programs which Adobe has pushed people into using via their Creative Cloud subscription service, where you only have access to it as long as you keep paying your fees, and don't have access to it at all if they decide to withdraw access to the version you need.



SWF is not the same format as the one known as Shockwave, Adobe Shockwave, Macromedia Shockwave, or Shockwave for Director. For that format, see Shockwave (Director).


Format PRONOM LoCFDD Wikidata
SWF 1–6 (Macromedia) fmt/104, fmt/105, fmt/106, fmt/107, fmt/108, fmt/109 - Q29011079, Q29011223, Q29011271, Q29011315, Q29011347, Q29011357
SWF 7 fmt/110 fdd000130 Q29011358
SWF 8 (Adobe) fmt/505 fdd000248 Q29011361
SWF 9–10 fmt/506, fmt/507 - Q29011363, Q29011365
SWF 11–30 fmt/757, fmt/758, fmt/759, fmt/760, fmt/761, fmt/762, fmt/763, fmt/764, fmt/765, fmt/766, fmt/767, fmt/768, fmt/769, fmt/770, fmt/701, fmt/772, fmt/773, fmt/774, fmt/775, fmt/776 - Q29011484, Q29011514, Q29011538, Q29011549, Q29011566, Q29011569, Q29011579, Q29011646, Q29011710 ,Q29011774, Q29011824, Q29011892, Q29011977, Q29012054, Q29012120, Q29012190, Q29012206), Q29012224 ,Q29012285, Q29012350
SWF 31-36 - - Q29017304, Q29017306, Q29017309, Q29017311, Q29017312, Q29017314


SWF files begin with a 3-byte ASCII signature:

  • "FWS" is for uncompressed files.
  • "CWS" is for files that use zlib compression.
  • "ZWS" is for files that use LZMA compression.

See also



Authoring Software

Inspection and Decompilation Software

Viewer Software


  • AS3: AS3swf - Low level library to parse, create, modify and publish SWF files.
  • AS3: AS3abc - Low level library to parse, create, modify and publish ABC (Actionscript Block Code) files.
  • AS3: SWFWire - SWF Decompiler and Inspector Tools.
  • AS3: Abc-abstraction - Allows ABC to be analyzed, manipulated, packaged back into an SWF, and run.
  • C#: SwfDotNet - Low level library to parse, create, modify and publish SWF files.
  • C/C++: Ming - SWF generation library
  • C++: gameswf - Library for parsing and rendering SWF movies
  • C++ libsswf - A complete library to generate Flash animations
  • PHP: Ming - SWF generation library
  • Python: Ming - SWF generation library

Sample files


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