head to head · open source
koreader vs citadel
koreader has 30,818 GitHub stars, 2,019 forks, 1,345 open issues and last shipped yesterday. citadel has 1,311 stars, 27 forks, 10 open issues and last shipped yesterday. koreader leads on adoption by 2,251% (30,818 vs 1,311 stars). koreader is written in Lua under AGPL-3.0; citadel is written in Rust under MIT. koreader has attracted 7% as many forks as stars, citadel 2%. koreader 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
| koreader | citadel | |
|---|---|---|
| GitHub stars | ★ 31K | ★ 1.3K |
| License | AGPL-3.0 | MIT |
| Written in | Lua | Rust |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 2.0K | ⑂ 27 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick koreader if
- You weight community size — 31K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches Lua
- 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 koreader
KOReader is a document viewer primarily aimed at e ink readers. [![AGPL Licence][badge license]](COPYING) [![Latest release][badge release]][link gh releases] [![Gitter][badge gitter]][link gitter] [![Mobileread][badge mobileread]][link forum] [![Build Status][badge circleci]][link circleci] [![Coverage Status][badge coverage]][link coverage] [![Weblate Status][badge weblate]][link weblate] Download • User guide • Wiki • Developer docs Main features portable : runs on embedded devices (Cervantes, Kindle, Kobo, PocketBook, reMarkable), Android and Linux computers. Developers can run a KOReader emulator in Linux…
read the full koreader 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 koreader or citadel more popular?
koreader has 30,818 GitHub stars and citadel has 1,311. koreader has the larger community by that measure.
Are koreader and citadel free?
Both are open source. koreader is licensed under AGPL-3.0 and citadel under MIT. Neither carries a licence fee.
What is the difference between koreader and citadel?
koreader is written in Lua 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, koreader or citadel?
Choose koreader if you want the larger community (30,818 stars) or its AGPL-3.0 licence terms. Choose citadel if its feature set, stack or MIT licence fits better. Both are self-hostable.