About
Free tools for the fiddly parts of 3D printing.
Nozzlefox is an independent project: no company behind it, no investors, no ads. It exists because opening, fixing and converting print files shouldn’t need an account, an upload or a paid app.
- Nothing uploadedYour files are opened and converted on your own device.
- No account, no adsNo sign-up, no cookies, no trackers, no upsell.
- Works offlineOnce a page has loaded, its tool keeps working without internet.
How the tools work
All 23 tools run inside your browser. When you drop a file, your browser reads it from your disk and the page’s own code does the work, in a background thread, with no server involved. That’s also why there’s no file size limit beyond your device’s memory, and why nothing is stored after you close the tab.
Some of the heavy lifting is done by well-known open-source engines:
- Open CASCADE, the CAD kernel FreeCAD uses, reads STEP files.
- Manifold makes the exact cuts, pins and repairs on solid models.
- meshoptimizer reduces triangle counts; three.js draws the 3D views.
Much of the rest is written for this site: the readers for 3MF, G-code, Prusa binary G-code (.bgcode) and Bambu .gcode.3mf files, the STEP and 3MF writers, the font reader behind the name tags, and the QR code encoder. Every library is credited on the licences page.
Check that your files stay on your device
You don’t have to take our word for it:
- Open your browser’s developer tools (F12), go to the Network tab, and convert a file. You’ll see the page load its own code, and no upload.
- Open a tool once, then switch off your internet connection. It keeps working, which it couldn’t if it needed a server.
The site’s security policy also tells your browser to block connections to any other server, on every page except Map to STL, which needs map data. The privacy page has the details.
How the tools are tested
- Real files, in a real browser. An automated check opens each tool in Chrome and gives it real files: Bambu Studio and PrusaSlicer projects, Prusa .bgcode and Bambu .gcode.3mf prints, CAD assemblies from the CAx-IF test library, 3D scans, textured models, photos. A tool that throws an error or doesn’t finish fails the check.
- Offline. A second check saves the site for offline use, cuts the connection and uses the tools from the cache.
- Unit tests cover the file readers and writers, the geometry (cuts, repairs, scaling), the QR encoder (checked against an independent decoder) and the cost maths.
- Standard files. Downloads follow the STL, 3MF, OBJ and STEP standards, in millimetres, so they open in Bambu Studio, PrusaSlicer, OrcaSlicer, UltiMaker Cura and CAD programs.
How the guides are written
The 14 guides answer questions people actually search for when a file won’t behave. Each one is written by hand, gives the short answer first, and says when it was last checked.
- Numbers come from real files where possible, and the guide says so (for example, how much smaller a .bgcode is than the same print as .gcode).
- Claims about slicers are checked against the slicers’ own source code and the makers’ documentation, and printer sizes against the makers’ spec pages. When a slicer changes, the guide is updated and its date changes.
Free, and staying free
There’s no paid version, no premium tier and no watermark, and the tools don’t get worse to sell you something. Running a static site costs very little, which is what makes that possible. If that ever changes, this page will say so first.