SFD (FontForge)
Also known as: .sfd file, Spline Font Database, FontForge source
SFD (Spline Font Database) is the native source format of FontForge, the open-source font editor. It stores a font project’s glyph outlines and settings as editable text, separate from the finished TTF or OTF you export.
- Native source format of the FontForge editor
- Text file holding outlines, hints, and metadata
- Exported to TTF or OTF for real use
SFD as a working file
An SFD is the editable project, much like a layered document in an image editor. It keeps every glyph’s spline outlines, hints, and metadata in a single text file that FontForge can reopen and refine.
It is specific to FontForge, whereas UFO is a tool-neutral source format aimed at interchange between editors.
From SFD to a usable font
You do not install an SFD. FontForge generates a TTF or OTF from it, which is the file an operating system or browser can actually use.