What is the FZZ file format?
A .fzz file contains complete project data for a design created with Fritzing, an open-source electronics prototyping and design application. Unlike a plain .fz sketch, a .fzz is a ZIP archive that bundles the main sketch together with any custom part definitions (.fzp and .fzpz files), making the project fully self-contained for sharing. The file is identified by the standard ZIP PK magic bytes (50 4B 03 04) at byte offset 0.
What is Fritzing?
Fritzing is an open-source CAD software tool for designing electronic devices, originally developed at the University of Applied Sciences Potsdam. The project's source code is written in C++ and is publicly available for anyone who wants to contribute.
What does Fritzing offer?
Although Fritzing is a free tool and offers considerably less advanced features compared to most paid alternatives, it is easy to navigate even for beginners and hobbyists. Users can design their own boards, add components across breadboard, schematic, and PCB views, and calculate parameters for a given system. Boards can be printed or ordered as physical PCBs through the FritzingFab service. The forum on the Fritzing website is the go-to place for exchanging .fzz projects with other enthusiasts.
Security & safety
RISK: LOWAn .fzz is a passive ZIP archive of design data (XML + SVG); it isn't executable and is safe to open in Fritzing. The only practical cautions are non-security: download Fritzing from the official fritzing.org (or trusted distro/Flatpak) rather than mirror sites that repackage it with adware, and be aware the official prebuilt download asks for a donation (the source remains free). As with any ZIP from an untrusted source, you could rename-and- inspect before opening, but the format itself poses no special risk.
Format details
in a nutshellPrograms that open FZZ files
Windows1 app
Fritzing
Open-source Install Fritzing and File > Open the .fzz (or just double-click it). Free/open source; the official binary asks for a donation. 
macOS1 app
Linux1 app
Fritzing
Open-source Install via the official download, distro package or Flatpak, then File > Open the .fzz. Technical details
deep spec| Container type | ZIP archive (PK format, DEFLATE compression) |
| Magic bytes | 50 4B 03 04 at offset 0 (standard ZIP PK signature) |
| MIME type | application/octet-stream |
| Internal sketch file | XML-based .fz file (primary design data) |
| Bundled part definitions | .fzp (XML part definition) and .fzpz (compressed part bundle) files |
| ZIP distinction | Distinguished from a plain ZIP by the presence of a .fz file inside the archive |
| Design views | Breadboard, Schematic, and PCB - three synchronized views per project |
| Export formats | Gerber, PDF, SVG, PNG, Eagle XML (.brd) |
| Platform support | Windows, macOS, Linux |
| Host application language | C++ (Qt framework) |
| XML character encoding | UTF-8 |
| Primary use case | Self-contained portable project bundle for sharing, with custom parts included |
| Single-sketch alternative | .fz stores only the sketch without bundled custom parts |
| Developer | Fritzing (originated at University of Applied Sciences Potsdam) |
| Fabrication service | FritzingFab - direct PCB ordering from .fzz designs |
| Released | circa 2009 (Fritzing 0.x) |
| Open standard | Yes · royalty-free |
| Specification | fritzing.org |
FZZ conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about FZZ files.
