head to head · open source
calibre vs kokoro-tts
calibre has 25,923 GitHub stars, 2,690 forks, 6 open issues and last shipped yesterday. kokoro-tts has 1,883 stars, 177 forks, 17 open issues and last shipped 27 days ago. calibre leads on adoption by 1,277% (25,923 vs 1,883 stars). calibre is written in Python under GPL-3.0; kokoro-tts is written in Python under MIT. calibre has attracted 10% as many forks as stars, kokoro-tts 9%. 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.
← all 8884 open source comparisons
Side by side
| calibre | kokoro-tts | |
|---|---|---|
| GitHub stars | ★ 26K | ★ 1.9K |
| License | GPL-3.0 | MIT |
| Written in | Python | Python |
| Last push | 2026-09-17 | 2026-08-22 |
| Forks | ⑂ 2.7K | ⑂ 177 |
| 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 kokoro-tts if
- You want the kokoro-tts feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches Python
- You evaluated both and kokoro-tts 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 kokoro-tts
kokoro tts is a Python command line text to speech tool built around the Kokoro model, and it lives in the open source Python text to speech and publishing ecosystem. The project wraps model inference in a CLI workflow so users can convert written text into spoken audio without building a separate speech pipeline.
read the full kokoro-tts overview →
More in Content & Publishing
Related comparisons
More Publishing projects
Compare either of these against the rest of the Publishing field.
Frequently asked questions
Is calibre or kokoro-tts more popular?
calibre has 25,923 GitHub stars and kokoro-tts has 1,883. calibre has the larger community by that measure.
Are calibre and kokoro-tts free?
Both are open source. calibre is licensed under GPL-3.0 and kokoro-tts under MIT. Neither carries a licence fee.
What is the difference between calibre and kokoro-tts?
calibre is written in Python and kokoro-tts 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 kokoro-tts?
Choose calibre if you want the larger community (25,923 stars) or its GPL-3.0 licence terms. Choose kokoro-tts if its feature set, stack or MIT licence fits better. Both are self-hostable.