Z3 File

What are Z3 files and how to open them

Are you having problems opening a Z3 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 Z3 files.

What is a Z3 file?

Z3 files have multiple uses, and Z-Code V3 Adventure For Infocom Z-Machine is one of them. Read more about the other uses further down the page.

Z-Code V3 Adventure For Infocom Z-Machine File

This file is a "story" module for version 3 of the Infocom Z-Machine virtual machine, used to run text adventure games created in the late 1970s and 1980s. It holds compiled game code (bytecode), text, puzzles, object definitions, and supporting data so interpreters like Windows Frotz can load and run the game exactly as Infocom intended. It functions like an executable specific to interactive fiction, not a document or media file.

Infocom created these files by compiling game source written in the Zork Implementation Language; interpreters designed for Z-Machine version 3 read them. Version 3 imposes fixed limits: files must not exceed 128 kilobytes, games may define at most 255 objects, only 32 attributes per object, simple property arrays of limited length, no bold or underlined text, and function calls allow at most 3 parameters.

Inside a Z3 file the first byte indicates version (value 3), followed by a header with fixed fields including flags, memory layout addresses, dictionary and object table offsets, checksum and release/serial identifiers. Example restrictions: object table entries are 9 bytes each, number of global variables capped at 240, and story file size length stored after version must be divided by a constant to fit.

How to open Z3 files

We have identified one Z3 opener that is compatible with this specific type of Z3 file.

Programs that open Z-Code V3 Adventure For Infocom Z-Machine files

Last updated: August 14, 2026

All known file formats using extension .Z3

While Z-Code V3 Adventure For Infocom Z-Machine File is a popular type of Z3-file, we know of 2 different uses of the .Z3 file extension. Different software may use files with the same extension for different types of data.

ZW3D Model

We know that one Z3 format is ZW3D Model. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

While we have not verified the apps ourselves yet, our users have suggested three different Z3 openers which you will find listed below.

Various apps that use files with this extension

These apps are known to open certain types of Z3 files. Remember, different programs may use Z3 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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