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fontmake compiles fonts from various sources (.glyphs, .ufo, designspace) into binaries (.otf, .ttf). You can use it to create static instances and variable fonts.


Fontmake requires Python 3.8 or later.

Releases are available on PyPI and can be installed with pip.

pip3 install fontmake

Use the -U, --upgrade option to update fontmake and its dependencies to the newest available release:

pip3 install -U fontmake

Basic Usage

After installation, you will be able to use the fontmake executable.

For example, to compile a variable font from a Glyphs source file, use:

fontmake MyFont.glyphs -o variable

The most important command line arguments to the fontmake executable are the required input, specified either as positional argument or using one of -g/-u/-m flags, and the optional -o flag, which chooses the output file format.

Source file format options

There are two ways to specify the source file or files:

One can either use the following, mutually exclusive, flags:

  • -g filename.glyphs: Converts a Glyphs source file to binary.
  • -u filename.ufo ...: Converts one or more UFO(Z) files to binary.
  • -m filename.designspace: Converts a Designspace file to binary. (The -m is for mutatormath, an old Python library for handling designspaces.)

Alternatively, one can specify the input(s) as positional arguments without the flag, letting fontmake infer the source format from the file extension: e.g. fontmake MyFont.designspace, etc.

Note: if the positional arguments are preceded by an option that takes one or more arguments, you need to use the special -- separator to mark all following arguments as positional (non-options), otherwise the parser gets confused. E.g., the -i option takes zero or one arguments (see futher below for details); without --, argparse thinks you didn't provide any inputs:

fontmake -i -- MyFont.designspace

Exactly one type of input can/must be specified, using either approaches.

Output file format options

You may provide one or more output file formats after the -o option. For example, -o otf ttf creates OTF and TTF binary font files for each master in your input file.

The following output file formats are available:

  • otf: Per-master OTF (CFF-outline) binaries. Placed in the master_otf/ directory.
  • ttf: Per-master TTF (TrueType-outline) binaries. Placed in the master_ttf/ directory.
  • otf-cff2: Per-master OTF binaries with CFF2 outlines. Placed in the master_otf/ directory.
  • variable: A TrueType variable font. Placed in the variable_ttf/ directory.
  • variable-cff2: A variable font with CFF2 outlines. Placed in the variable_otf/ directory.

The following output file formats are also available, but are generally used internally by fontmake as an intermediate step to one of the above outputs:

  • otf-interpolatable: OTF binaries suitable for merging into a variable font. Placed in the master_otf_interpolatable/ directory. (These differ from otf in that the outlines are unoptimized.)
  • ttf-interpolatable: TTF binaries suitable for merging into a variable font. Placed in the master_ttf_interpolatable/ directory. (The outlines are converted to quadratic curves in an interpolation-compatible way.)
  • ufo: Glyphs sources can be converted to UFO, or to UFO zip (.ufoz) format with the flag --save-ufo-as-zip. Placed in the master_ufo/ directory.

If no format option is specified, the default is -o otf ttf.

Other important command line options

  • -i (Interpolate instances): Having per-master binaries is not always what you expect; if you have defined instances ("exports") in your Glyphs file, they will not be generated by default. To generate them, pass the -i flag, which interpolates static instances, and places them in the instance_ttf/ or instance_otf/ directory as appropriate.

  • --output-dir <some_directory>: Places all output in the given directory, instead of the per-format directories mentioned above.

  • --output-path <filename>: This is only valid if the output is a single binary file, and writes the output to the given filename.

  • -f (Flatten components): Ensures that any glyphs which contain components which themselves contain components are decomposed to a single level. This is recommended as certain rendering environments do not correctly handle nested components - see this link for more details.

Advanced Usage





Developers can get the latest version of fontmake by cloning the git repository:

git clone
cd fontmake
pip install .

Developers who want to quickly test changes to the source code without re-installing can use the "--editable" option when installing from a local source checkout:

pip install -e .

It is recommended to install fontmake inside a virtual environment to prevent conflicts between its dependencies and other modules installed globally.

You could also use the pipx tool to automate the installation/upgrade of python apps like fontmake in isolated environments.

Releasing a New Version

  1. Commit and push your final changes for the new version.
  2. Create an annotated Git tag of the version number, with a prepended "v", like so: git tag -a v3.1.1
  3. Write the release notes into the tag message. They will show up as release notes on the release page in GitHub.
  4. Push the tag like so: git push origin v3.1.1, where origin is the name of the usual remote you want to push the version to.