head to head · open source
koodo-reader vs calibre
koodo-reader has 28,217 GitHub stars, 2,116 forks, 271 open issues and last shipped yesterday. calibre has 25,923 stars, 2,690 forks, 6 open issues and last shipped yesterday. koodo-reader leads on adoption by 9% (28,217 vs 25,923 stars). koodo-reader is written in JavaScript under AGPL-3.0; calibre is written in Python under GPL-3.0. koodo-reader has attracted 7% as many forks as stars, calibre 10%. calibre was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (ebook, epub), 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
| koodo-reader | calibre | |
|---|---|---|
| GitHub stars | ★ 28K | ★ 26K |
| License | AGPL-3.0 | GPL-3.0 |
| Written in | JavaScript | Python |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 2.1K | ⑂ 2.7K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick koodo-reader if
- You weight community size — 28K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches JavaScript
- You value the larger contributor base for long-term maintenance
pick calibre if
- You want the calibre feature set and don't need the biggest community
- You prefer the GPL-3.0 license terms
- Your stack matches Python
- You evaluated both and calibre fits your workflow better
About koodo-reader
Koodo Reader is a cross platform ebook manager and reader written in JavaScript and released under the AGPL 3.0 license. It runs on Windows, macOS, Linux, Android, iOS, and the web, and it is distributed both as downloadable desktop and mobile applications and as a hosted web version at web.koodoreader.com. The project lives in the JavaScript ecosystem, is developed with yarn and git, and has been maintained for roughly seven years, with a repository that carries about 28,000 stars and 2,100 forks.
read the full koodo-reader overview →
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 →
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Frequently asked questions
Is koodo-reader or calibre more popular?
koodo-reader has 28,217 GitHub stars and calibre has 25,923. koodo-reader has the larger community by that measure.
Are koodo-reader and calibre free?
Both are open source. koodo-reader is licensed under AGPL-3.0 and calibre under GPL-3.0. Neither carries a licence fee.
What is the difference between koodo-reader and calibre?
koodo-reader is written in JavaScript and calibre 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, koodo-reader or calibre?
Choose koodo-reader if you want the larger community (28,217 stars) or its AGPL-3.0 licence terms. Choose calibre if its feature set, stack or GPL-3.0 licence fits better. Both are self-hostable.