[GUI Plugin] CalibReader Sync

[CalibReader_]

CalibReader Sync

Brings what you do in the CalibReader app on iPhone or iPad back into your calibre library: read/unread, % read and the date you last read each book.

I'm the developer of CalibReader, an EPUB and PDF reader for iPhone, iPad and iPhone Duo that reads your calibre library from your own storage: Dropbox, OneDrive, a NAS over SMB, or a folder on the device. This plugin is its desktop half. The plugin is free; it is only useful together with the app, which is paid (3 books free, then $9.99 once). The app is in public beta on TestFlight now: https://testflight.apple.com/join/PVW2VU9c

What it does
The app keeps two small files in your library folder: CalibReader_sync.json (read/unread) and CalibReader_positions.json (where you are in each book). Once they have synced to the library folder on your computer, click Sync Read Status in calibre. The plugin:

• reads both files from the library that is currently open, and matches books by calibre UUID
• sets a Yes/No custom column, #read_status, for each matching book
• writes % read and last read into columns you choose in Settings; books under 1% read are skipped, so opening a book to look at it doesn't count
• reports how many books it updated, how many entries it left alone, and how many books aren't in this library

It has no network access and changes no column other than #read_status and the ones you chose. It writes to CalibReader_sync.json only to pass a newer calibre read status back to the app.

Use the columns you already have
Settings (the arrow next to the button) suggests existing columns that mean the same thing, such as Kobo Utilities' Percent Read or KOReader Sync's progress column. Integer (0-100) and percentage-formatted floating point columns both work. Or click Create column... and confirm it in calibre's own column dialog. The settings are saved in the library, so they follow it to other computers.

Conflicts
Every entry carries its own timestamp. The plugin remembers, per book, what it last applied (in its own preferences, not in your library), so an old entry can't apply twice, and a change you make to a book in calibre after the app's entry is not overwritten.

Setup
1. Install: Preferences > Plugins > Get new plugins and search for "CalibReader Sync", or download the zip attached to this post and use Load plugin from file. Restart calibre.
2. For read status, create the column once: Preferences > Add your own columns > Add custom column. Lookup name: read_status. Column heading: Read Status. Column type: Yes/No. Restart calibre.
3. For reading progress, open Settings from the arrow next to the button, pick or create the columns, then restart calibre if you created any.
4. Optional: Preferences > Toolbars & menus, and add "Sync Read Status" to the main toolbar.
5. Open the same library folder in calibre that the app reads.
If a column or a file is missing, the plugin says what to do.

Compatibility

• calibre 9.0 or later; tested on calibre 9.16 (Windows)
• Windows, macOS, Linux
• the CalibReader app on iPhone, iPad or iPhone Duo

Limitations

• Read status goes both ways: the app picks up calibre's read status when it syncs, and the newer change wins. % read and last read go from the app to calibre only.
• Read status goes into a Yes/No column named read_status for now; choosing your own column is coming in the next update. If you already have one, such as #read, the plugin spots it and shows how to copy it over once.
• It syncs by itself when calibre starts, when you open a library, and when the app's files change (checked every 5 minutes), with a short status-bar note and no pop-ups. The button syncs on demand, and Settings turns the automatic sync off.
• It works on the library that is currently open.

Links
Source: https://github.com/mklod/calibReader...eDesktopPlugin
Help page: https://calibreader.com/help/plugin
The app: https://calibreader.com
Questions about the plugin are welcome in this thread.

License
GNU GPL v3.

CalibReader is an independent app and is not affiliated with calibre.

Version History

Spoiler:

1.2.5, 2026-10-21
- Automatic sync: when calibre starts, when a library opens, and when the app's files change. A status-bar note, no pop-ups; a Settings switch, on by default.

1.2.4, 2026-10-21
- Read status stays in step both ways: a read status you change in calibre after the app's change is passed back to the app.

1.2.3, 2026-10-21
- Read status: an unrelated calibre edit (a rating, a tag) no longer drops a newer read mark from the app.

1.2.2, 2026-10-21
- If the library has no #read_status column but already has a Yes/No read column (#read, #finished...), the summary and Settings show how to copy it over once.

1.2.1, 2026-10-21
- calibre's command-line tools and server no longer load the plugin's GUI code (the toolbar action moved to its own module). No change to what a sync does.
- Tested on calibre 9.16.

1.2.0, 2026-10-12
- % read and last read go into columns you choose, from CalibReader_positions.json. Books under 1% read are skipped (adjustable).
- New Settings dialog with suggested columns and Create column; settings are saved in the library.
- #read_status must be a Yes/No column; a missing one no longer stops reading progress from syncing.
- Fixes: a late read-status entry could be skipped as if the book had been edited in calibre; installing over 1.1.x failed until calibre restarted.

1.1.1, 2026-10-09
- GPL v3 licence. Requires calibre 9.0 or newer.

1.1.0, 2026-09-15
- Each sync-file entry now has its own timestamp; older files are still read.
- Old entries no longer re-apply, and a change made in calibre is not reverted by the next sync.
- The result dialog also reports skipped entries.

1.0.0, 2026-06-09
- First release.

[CalibReader_]

Reserved for test versions.