HPJ File

What are HPJ files and how to open them

Are you having problems opening a HPJ 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 HPJ files.

What is a HPJ file?

HPJ files have multiple uses, and Armor Command Mission is one of them. Read more about the other uses further down the page.

Armor Command Mission

We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

How to open HPJ files

Important: Different programs may use files with the HPJ file extension for different purposes, so unless you are sure which format your HPJ 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 HPJ openers which you will find listed below.

Last updated: August 7, 2026

All known file formats using extension .HPJ

While Armor Command Mission is a popular type of HPJ-file, we know of 2 different uses of the .HPJ file extension. Different software may use files with the same extension for different types of data.

Microsoft Help Compiler Project

Microsoft Help Compiler Project (.HPJ) is a plain-text project file used with Microsoft's WinHelp system. It gathers information that the Help compiler (Help Workshop) uses to build Windows help files (.HLP) by defining which Rich Text Format (RTF) topic files, bitmaps, alias and map settings, window styles, and other resources are included, how they behave, and what compilation options to apply.

Help Workshop is the tool that creates and edits .HPJ files. Developers write or modify the .HPJ to list all source topics (RTF), images (such as BMP), mapping of topic IDs and aliases for lookup, layout and window definitions, and options like which build tags and flags to use. Once the .HPJ is ready, Help Workshop (or the Help Compiler it invokes) reads it together with the listed files to generate a compiled help file (.HLP), optionally also a contents file (.CNT) and other auxiliary outputs.

. HPJ files begin with a section header [OPTIONS] at offset 0 ("[OPTIONS]" plus a newline), followed by other sections such as [FILES], [CONFIG], [MAP], [ALIAS], [WINDOWS], [BITMAPS] and [BAGGAGE]. They contain strings such as "FILES" and ".RTF" to list topic files.

HPJ opener for Windows

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

Various apps that use files with this extension

These apps are known to open certain types of HPJ files. Remember, different programs may use HPJ 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 HPJ file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.