What Are Single Line Fonts?
Single line fonts — also called SLF, single stroke fonts, or open-path fonts — are a completely different class of typeface from the fonts you use on screen. They are built for machines: laser engravers, pen plotters, vinyl cutters, and CNC routers.
The problem with regular fonts on machines
TTF and OTF fonts are designed for inkjet and screen rendering. Every letterform is a closed, filled outline. When you import a "C" from a regular font into a laser engraver, you get two concentric arcs — the outer and inner edge of the stroke. The machine engraves both edges and fills the space between them. This is slow, creates double-burn lines at the stroke edges, and wastes material. For a pen plotter, it means every letter requires two separate pen strokes tracing the outline, with the interior left unfilled — a result that looks nothing like actual handwriting.
What single line fonts actually are
A single line font is a typeface where every letterform is a single open path — one continuous line from the start of the stroke to the end. There is no fill, no outline, no interior. A lowercase "a" in a single line font is a single stroke, the same way you would write it by hand. For a laser engraver, this means one pass per stroke. For a pen plotter, it means the pen stays down from the beginning to the end of each letter, lifting only between letters. The result is dramatically faster, cleaner, and more natural.
Open paths vs. closed paths
In SVG terminology, a closed path ends with a Z command — the last point connects back to the first, closing the shape. Single line fonts use open paths — paths with distinct start and end points. This is what enables the "single stroke" behavior. Most design software and machine control software can handle both, but they treat them differently. Pathhaus exports only open-path SVGs, ensuring your files behave correctly in LightBurn, Inkscape, xTool Creative Space, and every other machine software.
Where to use single line fonts
SLF fonts are ideal for laser engraving text on wood, acrylic, leather, and metal; pen plotting handwritten cards, certificates, and art prints; vinyl pen writing (not cutting — for cutting you need closed outlines); CNC light scoring and marking; and any application where you want fast, clean, single-pass text output. They are not suitable for screen display, inkjet printing, or any application that requires filled letterforms.
Try it in Pathhaus Studio
Free to start — optimize and export your first font file in under 5 minutes.