Optional Dependencies

The fonttools PyPI distribution also supports so-called “extras”, i.e. a set of keywords that describe a group of additional dependencies, which can be used when installing via pip, or when specifying a requirement. For example:

pip install fonttools[ufo,lxml,woff,unicode]

This command will install fonttools, as well as the optional dependencies that are required to unlock the extra features named “ufo”, etc.


Optional dependencies are detailed by module in the list below with the Extra setting that automates pip dependency installation when this is supported.


The module exports a ElementTree-like API for reading/writing XML files, and allows to use as the backend either the built-in xml.etree module or lxml. The latter is preferred whenever present, as it is generally faster and more secure.

Extra: lxml


Package for reading and writing UFO source files; it requires:

  • fs: (aka pyfilesystem2) filesystem abstraction layer.

  • enum34: backport for the built-in enum module (only required on Python < 3.4).

Extra: ufo


Module to compress/decompress WOFF 2.0 web fonts; it requires:

  • brotli: Python bindings of the Brotli compression library.

Extra: woff


To display the Unicode character names when dumping the cmap table with ttx we use the unicodedata module in the Standard Library. The version included in there varies between different Python versions. To use the latest available data, you can install:

  • unicodedata2: unicodedata backport for Python 3.x updated to the latest Unicode version 14.0. Note this is not necessary if you use Python 3.11 as the latter already comes with an up-to-date unicodedata.

Extra: unicode


Module for finding wrong contour/component order between different masters. It requires one of the following packages in order to solve the so-called “minimum weight perfect matching problem in bipartite graphs”, or the Assignment problem:

  • scipy: the Scientific Library for Python, which internally uses NumPy arrays and hence is very fast;

  • munkres: a pure-Python module that implements the Hungarian or Kuhn-Munkres algorithm.

Extra: interpolatable


Module for visualizing DesignSpaceDocument and resulting VariationModel.

Extra: plot


Advanced module for symbolic font statistics analysis; it requires:

  • sympy: the Python library for symbolic mathematics.

Extra: symfont


To get the file creator and type of Macintosh PostScript Type 1 fonts on Python 3 you need to install the following module, as the old MacOS module is no longer included in Mac Python:

  • xattr: Python wrapper for extended filesystem attributes (macOS platform only).

Extra: type1


Pen for drawing glyphs with Cocoa NSBezierPath, requires:

  • PyObjC: the bridge between Python and the Objective-C runtime (macOS platform only).


Pen for drawing glyphs with Qt’s QPainterPath, requires:

  • PyQt5: Python bindings for the Qt cross platform UI and application toolkit.


Pen to drawing glyphs as PNG images, requires:

  • reportlab: Python toolkit for generating PDFs and graphics.