Contributing guidelines

Contributions are welcome!

Big changes

Please open a new issue to discuss or propose a major change. Not only is it fun to discuss big ideas, but we might save each other’s time too. Perhaps some of the work you’re contemplating is already half-done in a development branch.

Code style

We use PEP8, black for code formatting and isort for import sorting. The settings for these programs are in pyproject.toml and setup.cfg. Pull requests should follow the style guide. One difference we use from “black” style is that strings shown to the user are always in double quotes (") and strings for internal uses are in single quotes (').


New features should come with tests that confirm their correctness.

New Python dependencies

If you are proposing a change that will require a new Python dependency, we prefer dependencies that are already packaged by Debian or Red Hat. This makes life much easier for our downstream package maintainers.

Python dependencies must also be license-compatible. GPLv3 or AGPLv3 are likely incompatible with the project’s license, but LGPLv3 is compatible.

New non-Python dependencies

OCRmyPDF uses several external programs (Tesseract, Ghostscript and others) for its functionality. In general we prefer to avoid adding new external programs.

Style guide: Is it OCRmyPDF or ocrmypdf?

The program/project is OCRmyPDF and the name of the executable or library is ocrmypdf.