defcon
A set of flexible objects for representing UFO data.
Decision gist · record as of 2026-08-14
Yes. Defcon is a stable, actively maintained library with low install friction and permissive licensing. It is the standard choice for UFO-based font manipulation in Python, with no known security vulnerabilities. Install it if you are building font editing tools or need programmatic access to UFO font data.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.9 or later.
- Low install friction with a single runtime dependency (fonttools).
- The project is actively maintained with recent commits and has been stable since its 2016 initial release.
License · maintenance · safety
MIT (permissive) — MIT license permits commercial and private use with minimal restrictions; you may use, modify, and distribute defcon freely provided you include the license notice.
last release 2025-07-16 (394 days) · last repo commit 2026-06-08 · 68 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 78,781 downloads/mo, #14,409 on PyPI
Alternatives
Verify before relying
pip install defcon
from defcon import Font
font = Font()
glyph = font.newGlyph('A')
contour = glyph.appendContour()- Whether optional extras (fontPens, lxml) are commonly needed for typical font editing workflows.
- Performance characteristics when working with large font files or complex glyph data.
What it is and what it does
Defcon is a Python library that provides a set of UFO (Unified Font Object) based classes for representing font data in a way optimized for font editing applications. It implements the UFO3 specification and offers lightweight, fast objects for working with glyphs, contours, and other font components. Rather than trying to be a complete solution, defcon provides bare-bones base functionality so developers can build their own font editing tools on top without managing object observation or cached data themselves.
The library depends on fonttools for core font operations and is designed to integrate into larger font editing workflows. It supports optional extras like fontPens for advanced glyph operations and lxml for faster XML parsing. The project is actively maintained and has been in use since 2016, making it a stable foundation for font tool development.
Use it for
- Building custom font editors or design tools that need to read, modify, and write UFO font files.
- Programmatically generating or manipulating glyphs, contours, and font metadata in font design pipelines.
- Converting between font formats or performing batch operations on font data using UFO as an intermediate representation.
- Developing font validation or analysis tools that need structured access to UFO font components.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
Defcon is a stable, actively maintained library with low install friction and permissive licensing. It is the standard choice for UFO-based font manipulation in Python, with no known security vulnerabilities. Install it if you are building font editing tools or need programmatic access to UFO font data.
Install
defcon on PyPI
Before you install
Low install friction with a single runtime dependency (fonttools). The project is actively maintained with recent commits and has been stable since its 2016 initial release.
Requires Python 3.9 or later.
License in practice
MIT license permits commercial and private use with minimal restrictions; you may use, modify, and distribute defcon freely provided you include the license notice.
Quickstart
pip install defcon
from defcon import Font
font = Font()
glyph = font.newGlyph('A')
contour = glyph.appendContour()Verify before relying
- Whether optional extras (fontPens, lxml) are commonly needed for typical font editing workflows.
- Performance characteristics when working with large font files or complex glyph data.
Package facts
| License | MIT permissive |
| Python support | Supports the current Python release >=3.9 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 1 packagefonttools |
| Maintenance | Actively maintained 394 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 78,781 / month, #14,409 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 4 - BetaIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseOperating System :: OS IndependentProgramming Language :: PythonProgramming Language :: Python :: 3Topic :: Multimedia :: Graphics :: Editors :: Vector-BasedTopic :: Software Development :: Libraries :: Python Modules |
Evidence: defcon-0.12.2-py3-none-any.whl
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See also cu2qu · ufoLib2 · glyphsLib · ufo2ft · fonttools · esphome-glyphsets · cffsubr · fontbakery · freetype-py · pymupdf-fonts