head to head · open source
calibre vs citadel
calibre has 26,327 GitHub stars, 2,743 forks, 6 open issues and last shipped yesterday. citadel has 1,311 stars, 27 forks, 10 open issues and last shipped yesterday. calibre leads on adoption by 1,908% (26,327 vs 1,311 stars). calibre is written in Python under GPL-3.0; citadel is written in Rust under MIT. calibre has attracted 10% as many forks as stars, citadel 2%. citadel was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 4 topic tags (calibre, ebook, ebook-manager, 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
| calibre | citadel | |
|---|---|---|
| GitHub stars | ★ 26K | ★ 1.3K |
| License | GPL-3.0 | MIT |
| Written in | Python | Rust |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 2.7K | ⑂ 27 |
| 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 citadel if
- You want the citadel feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches Rust
- You evaluated both and citadel fits your workflow better
About calibre
calibre calibre is an e book manager. It can view, convert, edit and catalog e books in all of the major e book formats. It can also talk to e book reader devices. It can go out to the internet and fetch metadata for your books. It can download newspapers and convert them into e books for convenient reading. It is cross platform, running on Linux, Windows and macOS. For more information, see the calibre About page. Screenshots Screenshots page Usage See the User Manual. Development Setting up a development environment for calibre. A tarball of the source code for the current calibre release. Bugs Bug reports and…
read the full calibre overview →
About citadel
Citadel Manage your ebook library with Citadel. Backwards compatible with Calibre. Project goals Backwards compatible with Calibre : Calibre must be able to read any library that Citadel has edited. Good UX : Citadel must be easy to use and look good. Performant : Citadel must feel much faster than Calibre, and never slower. Non goals Ebook reader : Citadel is not an ebook reader. There are already excellent ereader apps: Citadel will open your files in your default apps. ...or editor : If you're editing ebook content (not metadata like titles), Citadel will not be a replacement for you. 100% feature parity…
read the full citadel overview →
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Frequently asked questions
Is calibre or citadel more popular?
calibre has 26,327 GitHub stars and citadel has 1,311. calibre has the larger community by that measure.
Are calibre and citadel free?
Both are open source. calibre is licensed under GPL-3.0 and citadel under MIT. Neither carries a licence fee.
What is the difference between calibre and citadel?
calibre is written in Python and citadel in Rust. 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 citadel?
Choose calibre if you want the larger community (26,327 stars) or its GPL-3.0 licence terms. Choose citadel if its feature set, stack or MIT licence fits better. Both are self-hostable.