BookShelves includes a built-in Calibre wireless server. KOReader can connect to it directly — no Calibre desktop software needed. Once connected, you can push books from your Mac to your e-reader and import books that are only on the e-reader back into BookShelves. All over Wi-Fi.
This is different from OPDS, which lets KOReader browse and download from your library. Calibre wireless sync goes further: it’s a two-way connection where you actively push books to the device, and books the e-reader has that your library lacks can be imported back.
What You Need
- BookShelves Pro on your Mac (the Calibre wireless server is a macOS-only Pro feature)
- KOReader installed on your e-reader (Kindle, Kobo, PocketBook, or Android)
- Both devices on the same Wi-Fi network
Step 1: Enable the Calibre Wireless Server
- Open BookShelves on your Mac
- Go to Settings > Advanced
- Find the Calibre Wireless Server (KOReader) section
- Toggle Enable Calibre Wireless Server
- Optionally set a password for the connection
- Note the port number (default: 9090)
The status indicator turns orange when the server is listening and waiting for a connection.
Tip: The password is optional but recommended if you’re on a shared network. It’s stored securely in your Mac’s Keychain.
Step 2: Connect KOReader
- On your KOReader device, open the top menu
- Go to Calibre (or Network > Calibre)
- Select Wireless Settings > Server Address > Manual
- Enter your Mac’s IP address (e.g.,
192.168.1.100) and port 9090 - If you set a password in Step 1, enter it under Wireless Settings > Password
- Go back to the Calibre menu and tap Connect
KOReader will connect to BookShelves. The status indicator in BookShelves turns green and shows your device name.
Finding your Mac’s IP address: Go to System Settings > Wi-Fi > click Details on your active network. The IP address is listed there.
Step 3: Send Books to Your Device
Once connected, sending books is simple:
- In BookShelves, right-click any book in your library
- Select Send to Device > [your device name]
- The book transfers over Wi-Fi in a few seconds
The Settings panel shows a counter of how many books you’ve sent this session. Books land in KOReader’s library ready to read.
Pulling Books from Your Device
The sync works both ways. When KOReader connects, BookShelves can see the books on your device. If you have books on your e-reader that aren’t in your BookShelves library, you can import them back from Settings > Advanced while the device is connected.
Reading Position
Reading position does not sync between KOReader and BookShelves over Calibre wireless. BookShelves includes your percent read, finished status, finished date and rating in each book’s Calibre metadata, but KOReader’s Calibre plugin keeps only basic metadata such as title, authors, tags and series, so it does not apply them: KOReader opens each book at its own last position. KOReader reports no progress back over this protocol either, so what you read on the e-reader stays there.
BookShelves matches books between your device and library by their calibre identifier, or by author and title. A book on the e-reader that matches none in your library is listed under Settings > Advanced, where you can import it.
OPDS vs. Calibre Wireless — Which to Use?
Both methods connect KOReader to BookShelves. Here’s when to use each:
| OPDS | Calibre Wireless | |
|---|---|---|
| Direction | KOReader browses and pulls books | You push books from BookShelves |
| Reading position | Not synced | Not synced (KOReader keeps its own) |
| Book import | One-way (download only) | Push to the device; import device-only books from Settings |
| Auto-discovery | Yes (Bonjour) | Yes (UDP broadcast) |
| Best for | Browsing your library from the device | Sending specific books, and importing the device’s books |
You can use both at the same time — they don’t conflict. Many readers use OPDS for browsing their library on the device and Calibre wireless for pushing specific books.
For OPDS setup, see the KOReader OPDS guide.
Troubleshooting
KOReader Can’t Find the Server
- Same network? Your e-reader and Mac must be on the same Wi-Fi network. Guest networks often isolate devices.
- Check the IP. Your Mac’s IP may change if your router assigns addresses dynamically. Verify it in System Settings > Wi-Fi.
- Firewall blocking? macOS may block incoming connections. Go to System Settings > Network > Firewall and make sure BookShelves is allowed, or add port 9090 to the allowed list.
- Port in use? If something else is using port 9090, change the port in BookShelves settings. Remember to update KOReader’s server address to match.
Connection Drops After a Few Minutes
The server has a 5-minute idle timeout. If no books are being sent and no keepalive responses are received, the connection closes. This is normal — just reconnect from KOReader when you need to send more books.
Password Mismatch
If KOReader shows an authentication error, make sure the password in KOReader’s Calibre wireless settings matches exactly what you entered in BookShelves. The password is case-sensitive.
Books Not Appearing After Send
- Give KOReader a moment to process the received file. On older e-ink devices, file operations can take a few seconds.
- Check KOReader’s file browser — sent books appear in the default Calibre library folder on the device.
Reading Position Differs Between the Device and BookShelves
- This is expected: reading position does not sync over Calibre wireless with KOReader. KOReader does not apply the position BookShelves includes in a book’s metadata, and it reports no progress back, so each side keeps its own.
A Book on Both Sides Is Listed as Device-Only
- BookShelves matches books by calibre identifier, or by author and title. If the title or author differs between your library and the device, the match fails and the book is listed among the device-only books. Ensure the book has the same title and author in both places.
More troubleshooting
For Wi-Fi issues, router isolation, VPN interference, device-specific problems, and other connection failures, see the full KOReader troubleshooting guide.
What Formats Work?
BookShelves converts MOBI, AZW, AZW3, and PRC files to EPUB during import. When you send books via Calibre wireless, KOReader receives EPUB or PDF files — both of which it handles natively. No format issues to worry about.
What Is KOReader?
KOReader is a free, open-source ebook reader for e-ink devices. It runs on Kindle, Kobo, PocketBook, and Android, replacing the stock reading software with a feature-rich alternative. Its built-in Calibre plugin is what makes wireless sync with BookShelves possible — KOReader speaks the same protocol that Calibre desktop uses.
For a detailed comparison of KOReader and BookShelves, see BookShelves vs. KOReader.
Beyond KOReader
Any app or device that supports the Calibre Smart Device App protocol can connect to BookShelves’ wireless server. KOReader is the most common client, but the protocol is open and documented in Calibre’s source code.
For a complete overview of what BookShelves offers beyond device sync, see the full feature list.
Related guides
- How to Transfer Books to KOReader from Mac — overview of all methods (OPDS, Calibre wireless, email)
- Send Books to KOReader over OPDS — browse and download from the device
- KOReader Not Connecting? Fix Common Problems — detailed troubleshooting
- BookShelves vs. KOReader — feature comparison
Get BookShelves for your Mac
Calibre wireless sync is a macOS Pro feature. Free to try, one-time upgrade.
