How to read your Calibre library on iPhone and iPad

Calibre is where a lot of readers keep their ebook collections: thousands of books, tidy metadata, covers, series in order. Then you pick up an iPhone or iPad and look for the Calibre app, and there isn't one.

That does not mean your library is stuck on the computer. Here are three ways to get it onto iOS, from the simplest to the most comfortable.

There is no official Calibre app for iOS

Calibre is a desktop program for Windows, macOS and Linux. Its developers have not made an iPhone or iPad version, and the apps in the App Store with "Calibre" in their name are made by other people. What Calibre does have is a built-in web server, and that is what makes the next two options work.

Option 1: send books one at a time

For a handful of books, the quickest route is to put the file where your iPhone can see it.

1. In Calibre, select a book and choose Save to disk (or right-click and open the book's folder).
2. Copy the EPUB to iCloud Drive, Dropbox or Google Drive, or email it to yourself.
3. On the iPhone, open the file from the Files app or Mail and share it to your reading app.

This works with any reader, but it gets tedious fast, and you are copying files around instead of reading.

Option 2: the Calibre content server and OPDS

Calibre can share your library on your home network. Readers that understand OPDS, an open standard for book catalogs, can then browse it like a bookshop and download what you pick.

1. In Calibre, click Connect/share and choose Start Content server.
2. Calibre shows the address, usually your computer's local IP address with port 8080, for example http://192.168.1.20:8080.
3. In an OPDS-capable reader on your iPhone or iPad, add a catalog with that address followed by /opds, for example http://192.168.1.20:8080/opds.
4. Browse by title, author or series and download the books you want.

Your iPhone needs to be on the same Wi-Fi network as the computer, and the computer has to be awake with Calibre open. If you set a username and password for the content server in Calibre's preferences, enter them when you add the catalog.

Option 3: Calibre-Web, Kavita or Komga

If you would like your library available all the time, not only when your computer is on, a small server can serve it instead. Calibre-Web reads the same library folder that Calibre uses and adds a web interface and an OPDS feed, usually at /opds. Kavita and Komga are popular for mixed collections of books and comics, and both offer OPDS too (Kavita shows your personal OPDS address in your user settings).

These usually run on a home server, a NAS or a small computer that stays on. Once set up, your iPhone can reach the catalog at home, and from anywhere if you choose to expose it securely.

Downloading a book over OPDS, step by step

Whichever server you use, the reading side looks the same:

1. Add the catalog address (and your username and password if the server asks for them).
2. Open the catalog and browse or search.
3. Tap a book to see its cover and description, then download it.
4. The book appears on your shelf and opens like any other.

A good OPDS reader keeps the catalog in its list, so the next time you finish a book, the next one is two taps away.

Reading your Calibre books in Glosa

Glosa speaks OPDS. In the library, tap + and choose Catalogs (OPDS), then add the address of your Calibre content server, Calibre-Web, Kavita or Komga. Passwords are kept in the iPhone's Keychain. Project Gutenberg is there as a catalog to start with. Books you download land on your shelf as EPUB, PDF or DRM-free Kindle files, and your library, highlights and places sync between iPhone and iPad through iCloud.