Everything useCalibre does

A hosted catalog, web reader and OPDS feed for the Calibre libraries you keep in your own storage. Here is all of it, including what it deliberately doesn’t do.

Connect your Calibre library

• Storage you own: Amazon S3, Cloudflare R2, and any S3-compatible service (Backblaze B2, Wasabi, MinIO and others). Azure, OneDrive, Dropbox and Google Drive are planned.
• A read-only key is enough. useCalibre reads metadata.db, the covers and the book files; it never writes to a library Calibre manages.
• Damage check first. A half-synced metadata.db is refused and the last good import is kept, so a bad sync never empties your catalog.
• Stays current. useCalibre checks for a new metadata.db every few minutes; changes made in Calibre appear by themselves.
• Several libraries, one view. Connect up to five Calibre libraries to one library. A book that is in more than one shows once, with every copy on its page, so if one bucket is down you can read another copy.

Browse and search

• Covers, titles, authors and series in a grid, sorted by title, author or date added.
• Search across title, author, series and tags; filter by author, series, tag, reading status and source.
• A page for each book: description, publisher, published date, language, identifiers and every format.
• Reading progress on every cover, and a “Finished” badge when you are done.

Read in the browser

• Make it yours: white, sepia, gray or night pages; original, serif, sans or a highly readable font; text size, line spacing, width and justification.
• Your place, everywhere: progress is saved as you read and picks up on any device; the footer shows the chapter and pages left in it.
• Arrow keys, edge taps, and a clear end of book with “Read again”.

E-readers, phones and tablets

• OPDS catalog for KOReader (Kobo, Kindle, PocketBook), Readest, KyBook, PocketBook Reader, Moon+ Reader, Thorium, Panels and others. Each app gets its own password that you can remove on its own. Kobo and KOReader guide.
• Downloads go straight from your storage through a link that lasts ten minutes, never through our servers.
• iPhone and iPad: add useCalibre to the Home Screen, or send a book to Apple Books in one tap. iPad and iPhone guide.

Offline reading

• “Save for offline reading” saves a book on the device you are using; it opens with no connection, even signed out.
• Pages you read offline are synced when you are back online.
• The Offline shelf lists what is on the device and how much space it uses.

Family and several libraries

• Share a library with up to ten people as viewers (read and download) or editors (also add and edit books).
• Keep up to three libraries of your own, for example yours and the children’s, and switch between them.
• Everyone’s reading progress is their own.

Optional: let useCalibre manage a library

If you’d rather not run Calibre desktop at all, switch a library to useCalibre manages. Then you can upload books straight from your browser to your own bucket (the file never passes through our servers), edit titles, authors, series, tags, descriptions and covers, and delete books.

• Switching takes a backup of metadata.db and every metadata.opf first.
• Anything changed or deleted goes to a trash folder in your bucket for 30 days, and deleted books can be restored.
• Books are kept in Calibre’s own folder layout with a metadata.opf each, so Calibre can open the library again with Restore database.
• If Calibre desktop changes the library while useCalibre manages it, useCalibre stops and asks which copy to keep. It never overwrites silently.

Privacy and security

• Sign in with a password, Google or Microsoft; passkeys and two-factor authentication are built in.
• Storage keys and two-factor secrets are encrypted; each library is walled off by the database itself.
• No ads, no tracking cookies, no selling data. Privacy policy.

What it doesn’t do

• It doesn’t remove DRM, and DRM-protected books can’t be read in it.
• It doesn’t store your books for you; they stay in your storage.
• It doesn’t replace Calibre desktop for converting formats or fetching metadata.