What is the JFPROJ file format?
A .jfproj file is a project saved by Microsoft Font Maker, a free Windows app that turns your handwriting into an installable font. The name stands for JSON Font Project, and the file really is plain .json text, so you can peek inside it with any editor. Font Maker records each letter you draw with an active pen on a touchscreen, or with a mouse if you do not have one, and stores those glyphs together with the sample sentences you wrote to tune spacing.
Inside the JSON you will find the individual character shapes, the gaps between letters and words, and the overall font size. The .jfproj is the editable working copy of the font. It is not the finished product you install, and it only means something to Font Maker itself.
Security & safety
RISK: LOWA .jfproj is a plain-text JSON document with no executable code, macros or embedded binaries, so opening one cannot run anything on its own. The only realistic concern is a corrupted or hand-edited file failing to load in Font Maker. Treat unexpected files from unknown senders with normal caution, but the format itself carries no inherent malware risk.
Format details
in a nutshellPrograms that open JFPROJ files
Windows3 apps
Notepad
Built-in Right-click the .jfproj, choose Open with Notepad, and read the JSON contents directly without any extra software. 
Microsoft Font Maker
Free Install Microsoft Font Maker from the Microsoft Store, choose Open project, and load the .jfproj to keep editing your handwriting font or export it to TTF. 
Visual Studio Code
Free Open the .jfproj in VS Code to inspect the raw JSON glyph and spacing data as plain text, since it cannot render the font itself. Technical details
deep spec| Encoding | UTF-8 / ASCII plain text |
| Byte order | N/A (text format) |
| Container | JSON object |
| Typical size | A few kilobytes to a few hundred kilobytes, depending on the number of glyphs recorded |
| Structure | A single JSON document that stores a handwriting-based font project. It holds the individual glyphs (character outlines) captured from pen or mouse input, the sample sentences the user wrote, and metadata such as inter-character spacing, word spacing and font size. Because it is plain JSON, it can be inspected in any text editor. |
| Integrity | None built in |
| Platforms | Windows 10, Windows 11 |
| Notes | Created and read exclusively by Microsoft Font Maker, a free UWP app from the Microsoft Store. The .jfproj file is the editable working copy; the finished font is exported separately as a TrueType .ttf file. Input can come from an active pen on a touchscreen or from a mouse. |
| Released | 2018 |
| Specification | docs.fileformat.com |
JFPROJ conversions
Community Q&A
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