head to head · open source
calibre vs PyMuPDF
calibre has 25,923 GitHub stars, 2,690 forks, 6 open issues and last shipped yesterday. PyMuPDF has 10,732 stars, 798 forks, 58 open issues and last shipped yesterday. calibre leads on adoption by 142% (25,923 vs 10,732 stars). calibre is written in Python under GPL-3.0; PyMuPDF is written in Python under AGPL-3.0. calibre has attracted 10% as many forks as stars, PyMuPDF 7%. calibre was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (epub, python), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| calibre | PyMuPDF | |
|---|---|---|
| GitHub stars | ★ 26K | ★ 11K |
| License | GPL-3.0 | AGPL-3.0 |
| Written in | Python | Python |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 2.7K | ⑂ 798 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick calibre if
- You weight community size — 26K stars and counting
- You want the GPL-3.0 license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick PyMuPDF if
- You want the PyMuPDF feature set and don't need the biggest community
- You prefer the AGPL-3.0 license terms
- Your stack matches Python
- You evaluated both and PyMuPDF fits your workflow better
About calibre
calibre is the official source code repository for the calibre e book manager, an open source application written in Python and released under GPL 3.0. It lives in the content and publishing ecosystem as a desktop tool for books, and it is cross platform, running on Linux, Windows and macOS. The project has been hosted on GitHub for roughly thirteen years, carries about 25,900 stars and 2,683 forks, and its home on the web is calibre ebook.com, where an About page and a screenshots page document it further.
read the full calibre overview →
About PyMuPDF
PyMuPDF is a high performance Python library, built on the MuPDF C engine, for extracting, analysing, converting, rendering and manipulating PDF and other documents, aimed at Python developers building data extraction, document processing and AI retrieval pipelines.
read the full PyMuPDF overview →
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Frequently asked questions
Is calibre or PyMuPDF more popular?
calibre has 25,923 GitHub stars and PyMuPDF has 10,732. calibre has the larger community by that measure.
Are calibre and PyMuPDF free?
Both are open source. calibre is licensed under GPL-3.0 and PyMuPDF under AGPL-3.0. Neither carries a licence fee.
What is the difference between calibre and PyMuPDF?
calibre is written in Python and PyMuPDF in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, calibre or PyMuPDF?
Choose calibre if you want the larger community (25,923 stars) or its GPL-3.0 licence terms. Choose PyMuPDF if its feature set, stack or AGPL-3.0 licence fits better. Both are self-hostable.