A3C File

What are A3C files and how to open them

Are you having problems opening an A3C 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 A3C files.

What is an A3C file?

An .A3C file is an Alan V3 Compiled Adventure file.

Alan V3 Compiled Adventure is the compiled game code format used by Alan Version 3 of the Alan Interactive Fiction system. It stores a fully processed adventure including all locations, objects, rules, and story logic in a form that the Alan interpreter can run directly. It is the main output that players run to play the interactive fiction game.

A3C files are produced by the Alan compiler (often from Alan source files written in .alan) as the adventure code file. Alongside an .a3c file, games that use multimedia will also produce a resource file .a3r containing images and sounds; to distribute the game you must include both .a3c and .a3r. The .a3c file itself holds all the game logic and structure; the interpreter loads it into memory, builds internal data structures (world, parser, rules, etc.), then runs its instructions.

Internally the .a3c file begins with the ASCII signature ALAN followed by a zero byte at offset 0. This signature identifies the file as an Alan V3 Compiled Adventure code file.

How to open A3C files

Important: Different programs may use files with the A3C file extension for different purposes, so unless you are sure which format your A3C file is, you may need to try a few different programs.

While we have not verified the app ourselves yet, our users have suggested a single A3C opener which you will find listed below.

Last updated: August 16, 2026

Various apps that use files with this extension

These apps are known to open certain types of A3C files. Remember, different programs may use A3C files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about A3C file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.