AS2PROJ File

What are AS2PROJ files and how to open them

Are you having problems opening an AS2PROJ file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your AS2PROJ files.

What is an AS2PROJ file?

An .AS2PROJ file is a FlashDevelop ActionScript 2 Project file.

A FlashDevelop ActionScript 2 Project file holds all of the configuration and data needed for building a Flash application using ActionScript 2 in the FlashDevelop IDE. It keeps track of things like which source files to compile, what assets to embed, build options, excluded paths, SWF output settings (such as background color, frame rate, and dimensions), pre- and post-build commands, and general project options like warnings, trace behavior, strict mode, and other compiler/debugger flags.

This format is written and read by FlashDevelop when creating and managing ActionScript 2 projects. Developers establish an AS2 project via FlashDevelop's New Project feature, after which all settings are saved into this file. FlashDevelop uses this file to re-open the project, determine what files to compile, how to package the output SWF, and which build commands to run.

Internally the file is an XML-based document encoded in UTF-8. It begins with an XML declaration (for example "<?xml version=\"1.0\" encoding=\"utf-8\"?>") followed by a root <project> element. The internal content includes tags for CLASS FILES TO COMPILE, PATHS TO EXCLUDE, ASSETS TO EMBED, OUTPUT SWF OPTIONS, BUILD OPTIONS, PREBUILD and POSTBUILD commands, and settings like OPTION WARNUNUSEDIMPORTS, OPTION STRICT, MOVIE WIDTH/HEIGHT/FPS/BACKGROUND, OPTION SHOWHIDDENPATHS, OPTION LIBRARYPREFIX, OPTION TRACEFUNCTION, OPTION VERBOSE, OPTION USEMAIN, OPTION INFER, OPTION USEMX, COMPILETARGETS, and more. There are also specific fields like MOVIE DISABLED, MOVIE INPUT, XML VERSION, among others. The file is identifiable by one or more strings among its early content, and by the presence of those keywords. Evidence of this format includes a byte signature beginning with the UTF-8 BOM followed by "<?xml version="1.0" encoding="utf-8"?>", followed by the <project> tag and the various option keywords.

How to open AS2PROJ files

Important: Different programs may use files with the AS2PROJ file extension for different purposes, so unless you are sure which format your AS2PROJ file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested seven different AS2PROJ openers which you will find listed below.

Last updated: August 20, 2026

Various apps that use files with this extension

These apps are known to open certain types of AS2PROJ files. Remember, different programs may use AS2PROJ files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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