Manage your ebooks. Without frustration.
Citadel is a fast, minimalist desktop app for managing your ebook library. Shelves, metadata, covers, search. It works with your existing Calibre library, on your computer.
Simple desktop software
No import step. No server install. Open Citadel and select your existing Calibre library: your new books and book edits are shared with Calibre.
- Browse without waiting
- Don't get slowed down. Whether your library is 50 books or 50,000 books, Citadel works just as fast. Feeling slow? Report it. Slow Citadel is a bug.
- An app you can understand
- We care about how you use Citadel, and we designed it to be easy to use. We trimmed the fat and built a tool that does one job well.
- Sane library layout
- Books are organized by author and book title. Folders contain your ebooks, covers, and Calibre-specific metadata. Any tool that can read your Calibre library works with Citadel. You can still use Calibre-Web.
Library/
├── metadata.db
└── Martha Wells/
└── All Systems Red (155)/
├── All Systems Red.epub
├── cover.jpg
└── metadata.opfWhat it does
Add books
Expand your collection, saving new EPUB, MOBI, CBZ or other ebook files into your existing library.
Book info from real libraries
Stop editing by hand. Fetch titles, authors, covers, and identifiers from Hardcover, Open Library, the United States Library of Congress, Deutsche Nationalbibliothek, and K10plus. Or, keep editing by hand.
Search, sort, shelve
Filter as you type, sort how you think, and keep smart shelves (Unread, a series, an author) that update themselves.
Not a reader, on purpose
Citadel manages the shelf and opens books in whatever app you already read with. One job, done well.
Designed for macOS, works on Linux
Real window materials, system type, keyboard-friendly controls. It behaves like a Mac app because it is one. Linux builds ship too.
You asked, we answered
Is Citadel compatible with Calibre?
Yes, Citadel works with your existing Calibre library, and Calibre will keep working with the same library. If you have any compatibility issues, please file an Issue on GitHub! We don't recommend running both apps at the same time, however.
Do I need to run a server?
No. Most ebook library tools today (Calibre-Web, Kavita, Komga, Colibri, Grimmory, HomeBranch) are "servers" you host and visit in a browser. Citadel is a desktop app: it opens the library on your disk directly, works offline, and needs no setup. If you also want remote access, a server like Calibre-Web can read the same library alongside it.
Do I need an existing library?
You don't! You can always create a new library in Citadel.
Can I read books in Citadel?
No, by design. Citadel manages the library and opens each book in your default reading app. It aims to do the shelf really well rather than be another mediocre reader.
Does Citadel convert ebook formats?
No. Conversion is Calibre's home turf, and both apps share the same library: convert in Calibre and the result shows up in Citadel.
Is it safe to use on my real library?
Yes, but compatibility always has risks. It's possible that Calibre changes behaviour that breaks Citadel. Keeping backups of your library (specifically the metadata.db file) is always a good idea.
What platforms does it run on?
macOS (Apple Silicon) and Linux (AppImage, .deb, .rpm) today. Windows builds aren't published yet; watch the GitHub releases page for when that changes.
How much does it cost?
Nothing. Citadel is free, open-source software under the MIT license.
Where do I report bugs or ask questions?
On GitHub: issues for bugs, discussions for questions and ideas. Early-stage projects live on this kind of feedback.
Something else on your mind? Ask in the GitHub discussions.