catpaq

GUI for ZPAQ archives powered by zpaqfranz. Browse versions, extract files, test integrity and ADD new content — no installation required

Compared to most other GUIs for ZPAQ archives, it is possible to CREATE archives, not just extract their contents, in a way conceptually similar to interfaces like 7-Zip, WinRAR, and so on.

catpaq screenshot The name of this project is a tribute to my beloved cat Sharon Stone, nicknamed Frufru. I miss her so much. :sob:

ZPAQ is one of the best compression formats around — great compression ratio, incremental backups, full version history. The catch: it has no official GUI. catpaq fixes that. Drop it next to zpaqfranz, open an archive, and you're done.

Features

Browse any ZPAQ archive — see all files and folders, with full version history
Time machine — navigate between archive snapshots and extract any past version of a file
Integrity test — verify your archive with real-time progress and ETA, results shown directly in the log
Add files — select files and folders from the built-in file explorer and add them to any archive
Extract — extract single files, folders, or everything, with GUI destination picker
Encrypted archives — supports zpaq's AES and zpaqfranz's Franzen password protection
Filter & search — quickly find files inside large archives
Hash calculation — CRC32, SHA256, BLAKE3, XXH3 and many more, with clipboard copy on single file
Portable — no installer, no registry, no admin rights needed (unless you want file associations)
Cross-platform — runs on Windows, Linux and macOS (work in progress)

Requirements

Catpaq is a front-end: it needs the zpaqfranz executable to do the actual work, and will offer to download it for you (on Windows). BTW zpaqfranz official repository

Installation

No installer required.

Download the latest release from the Releases page
Unzip the archive to any folder you like
Place zpaqfranz (zpaqfranz.exe and zpaqfranz.dll on Windows) in the same folder
Run catpaq.exe (Windows) or catpaq (Linux/macOS)

Technical detail.
Each version of catpaq keeps the SHA-256 hashes of both zpaqfranz.exe and zpaqfranz.dll hardcoded internally. This is done to limit the possibility of code “injection”. Therefore, attention must be paid to keeping catpaq.exe, zpaqfranz.exe, and zpaqfranz.dll aligned (in the directory from which they are executed).

It is possible that, in the future, I will change this policy, i.e., I may generate a single .EXE for Windows. However, I must also consider portability to different systems (Mac, Linux), on which I have not yet performed enough experiments.

These are the first releases; the work will improve over time.

(Windows) To open .zpaq files directly from your file manager, run catpaq as Administrator and use Settings → Associate .zpaq and .zpaq.franzen.

Screenshots

| Archive browser | Integrity test | File explorer | |---|---|---| | Browse | Test | |

How it works

Catpaq is a GUI layer over zpaqfranz. Every action — listing, extracting, testing, adding — translates into a zpaqfranz command that runs in the background. Output is streamed live into the Log tab, so you always see exactly what's happening.

The Add tab is a built-in file explorer: navigate your drives, select files, and send them to any archive in a few clicks. No drag-and-drop from an external window needed.

The use of two different modes (DLL and EXE) is designed to maximize the performance of archive listing. For simplicity reasons, the DLL incorporates a lot of superfluous code, but it is much easier to keep aligned with the EXE.

In the new releases of zpaqfranz, you can notice the management using the DL define. Essentially, it is a matter of using direct operating system callbacks instead of Lazarus’s own mechanisms.

Building from source

Catpaq is written in Free Pascal / Lazarus. To build it yourself:

Install Lazarus (developed on version 4.4, FPC 3.2.2)
Clone this repository
Open catpaq.lpr in the Lazarus IDE
Build → Compile

Almost no external dependency

For updating hardcoded hashes you can use newcat.cpp https://github.com/fcorbelli/catpaq/blob/main/work/newcat.cpp

Credits

Catpaq is a front-end for zpaqfranz by Franco Corbelli, which is itself based on ZPAQ by Matt Mahoney.

All the heavy lifting — compression, encryption, verification — is done by zpaqfranz.

License

MIT — see LICENSE for details.

Catpaq

Install / Use

README