self-intersecting
A contour crosses itself. Rasterisers fill the overlap unpredictably depending on fill-rule (even-odd vs non-zero).
One-click Fix
Patens is a design tool for designing beautiful typefaces — with some assistance.
Proof · 30 seconds
Watch a glyph happen.
One unbroken take in the editor: draw a lowercase a, trace it to Béziers, let the audit read the result, apply a one-click fix, kern the new letter against V, and export an OTF you could install right now. No cuts, no speed-ups.
Proof · Specimen
What it makes.
Studio Geometric — drawn in Patens, exported by Patens, shipped as the editor's demo OTF. It's not a marketing typeface; it's the kind of work the editor produces end to end, from a blank canvas to an installable file.
Patens
Studio Geometric · Regular · 162 glyphs · Latin / Cyrillic / Greek · Drawn in Patens · 2026
The Method · Mentor in the margin
Every glyph gets a margin reading.
Patens runs all 105 rules continuously. When a contour crosses itself, when an x-height drifts, when a sidebearing wanders from its class — the audit notes it in plain English, beside the glyph, while you draw. Around 30 codes also offer a one-click fix; the rest are matters of judgment.
a
describeAuditCode() — one dictionary, five surfacesxheight-misaligned
A lowercase letter that should reach x-height is sitting noticeably below it. Uneven tops across letters give text a wobbly rhythm; consistent x-height alignment is what makes type read smoothly.
Designer judgment
sidebearing-class-drift-lsb
This glyph's LSB has drifted from the median of its sidebearing-class peers. Either re-apply the class or remove this glyph from it.
Designer judgment
Read the Method → · Full reference (105 codes) · Also
from the terminal: npx patens audit
Interface · Where you'll work
One tab. No install. No account.
Patens runs entirely in the browser. Projects live in your IndexedDB; nothing leaves the machine unless you choose to share. The audit panel sits to the right of the canvas and updates as you draw.
patens · Studio Geometric · saved 2 min ago
brief spacing features release export
Glyphs · 162
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
a
b
c
d
e
f
g
h
i
a
Audit 4
- near-collinear-points
contour 1, points 4–6
- xheight-overshoot
+14u above x-height
- aperture-asymmetric
right side −6u
- stem-thickness
+8% bottom downstroke
Editor surface — actual layout. Findings are real audit codes.
What the audit checks · 9 families, 105 rules
Contour to brief, everything reads.
The 105 codes group into nine families. Each one runs continuously; each one has plain-English prose attached. Click to expand a family — the codes inside are the actual checks running against every glyph as you draw.
01 Contour shape 9 codes
Self-intersection, winding direction, near-collinear nodes, sharp kinks. The geometry that decides how the glyph rasterizes at every size.
self-intersecting · winding-collision · sharp-kink · near-collinear-points
02 Vertical metrics + topology 12 codes
Ascender, descender, cap-height, x-height, baseline. The framework every letter hangs on; drift here breaks reading rhythm before any single letter looks wrong.
cap-above-ascender · xheight-misaligned · win-clip-top · use-typo-off
03 Spacing + sidebearings 9 codes
Left + right sidebearings, advance widths, class drift. The optical balance type designers calibrate by eye in strings like nnnonnon — now checked continuously.
overflows-advance · deeply-negative-lsb · sidebearing-class-drift
04 OpenType invariants 11 codes
Duplicate names, orphan classes, empty features, kern enabled with zero pairs. The plumbing that has to be right or the font silently misbehaves in downstream apps.
duplicate-glyph-name · pair-orphan-class · feature-kern-disabled-with-pairs
05 Naming + metadata 13 codes
Family, style, version, vendor ID, license, glyph-name canonicality. What downstream apps read to identify the font, and what reservation-of-name licenses (OFL) require you to change in derivatives.
naming-family-style · vendor-id-invalid · glyph-name-not-canonical
06 Coverage 7 codes
Latin-1 supplement, typographic essentials, currency, math symbols. Scripts you claim to cover and what those scripts actually require to be useful for setting real text.
coverage-typo-essentials · coverage-latin-1-supp · coverage-currency · coverage-math
07 Anchors 4 codes
Mark-positioning anchors — base, mark, ligature. The GPOS layer that makes diacritics sit correctly across the alphabet, in every accented language.
mark-no-prefix · base-with-prefix · anchor-without-partner
08 Variable fonts 9 codes
Master contour counts, axis ranges, named instances. The constraints that must hold for a variable font to interpolate cleanly without producing surprise glyphs between masters.
master-contour-count · axis-out-of-range · no-instances
09 Color · brief · misc 23 codes
COLR/CPAL palette consistency, project-brief completeness, tabular figures for data tables, and the long tail of practical checks designers internalize over years.
palette-length-mismatch · brief-no-intent · figures-non-tabular
Compared · Where Patens fits
Among the rest of the field.
Most rows in a font-editor comparison are tied — every modern editor draws Béziers and exports OpenType. These are the rows where Patens is different.
| Feature | Patens | FontLab | Glyphs | Fontra | Robofont | Glyphr Studio | Lipi | Fontish |
|---|---|---|---|---|---|---|---|---|
| Price | Free | $499 | $300 | Free | $400 | Free | Freemium | $6.49+/mo |
| Open source | MIT | — | — | BSD | — | MIT | — | — |
| Runs in the browser | ✓ | — | — | ✓ | — | ✓ | ✓ | ✓ |
| Pressure-sensitive sketch | ✓ | — | — | — | — | — | — | — |
| 105-code teaching audit | ✓ | partial | partial | — | partial | — | — | — |
| One-click "Fix" actions | ✓ | — | — | — | — | — | partial | partial |
| Plain-English explanations | ✓ | — | — | — | — | — | — | — |
— Alejandro, maker · with audit notes · more about who, why, and what's under the hood