fontParts 1.1.0

An API for interacting with the parts of fonts during the font development process.

FontParts

An API for interacting with the parts of fonts during the font development process. FontParts is the replacement for RoboFab. The project has a MIT open-source licence.

The documentation is at fontparts.robotools.dev.

This is a work in progress. We are still working out the API, abstract implementation, example implementation, test suite and documentation.

Want to contribute?

Thank you! Please see the CONTRIBUTING.rst file for a guide on how to help.

Also, feedback is very much welcome, please open an issue when you run into something that you wish fontParts did/didn’t do.

We ask that you work against the dev branch, the main branch is for releases only as of July 2026.

Installation

FontParts requires Python 3.10 or later.

The package is listed in the Python Package Index (PyPI), so you can install it with pip:

pip install fontParts

If you would like to contribute to its development, you can clone the repository from Github, install the package in ‘editable’ mode and modify the source code in place. We recommend creating a virtual environment, using the venv module.

# download the source code to 'fontParts' folder
git clone https://github.com/robotools/fontParts.git
cd fontParts

# create new virtual environment called e.g. 'fontParts-venv', or anything you like
python -m venv fontParts-venv

# source the `activate` shell script to enter the environment (Un\*x); to exit, just type `deactivate`
. fontParts-venv/bin/activate

# to activate the virtual environment in Windows `cmd.exe`, do
fontParts-venv\Scripts\activate.bat

# install in 'editable' mode
pip install -e .

Roadmap

We are still working on further tests, but are a stable 1.0 release.

• 0.8 Initial releases. Python 2 & 3. 2018-09-21

• 0.9 Python 3 only. 2019-08-30

• 1.0 Documentation and testing mostly complete. Added typing. 2026-05-28

• 1.5 Removal of Deprecated. Released 1 year after 1.0.

Testing

Testing is setup so that each environment that includes fontParts can provides the objects needed to run a common set of tests. This makes testing very easy for environments that use fontParts (for example, see the fontshell test.py script), but it means testing is different than other python packages.

Automated testing of the package is done in the fontshell environment. fontshell is fontParts for the commandline, implemented with defcon and is included as part of the fontParts package.

Before you can run the test suite you’ll need to install the test dependencies:

pip install -r requirements-dev.txt

To run the test suite you can do:

python Lib/fontParts/fontshell/test.py

To test in other environments, run the test script provided by that environment.