What ComBook does with your data
Last updated 1 October 2026. Applies to ComBook for iPhone and iPad, and to this website.
In short: ComBook has no account, no analytics, no ads and no tracking, and I collect no data from the app. What you read, where you are in it and what you highlight stays on your device, or goes to the servers and the iCloud account you choose.
On your device
Your library, the book files, reading positions, highlights, notes, bookmarks, reading stats and settings are stored in the app's own storage on your device. Server passwords and API keys are kept in the iOS Keychain. Deleting the app deletes all of it.
Servers you add
When you connect Kavita, Komga, an OPDS catalog or a KOReader sync server, ComBook contacts only the addresses you enter, with the credentials you give it. It downloads books, covers and pages. Depending on the server, it sends back your reading position, highlights, notes and bookmarks; the sync table lists which server receives what.
A KOReader sync server also receives a fingerprint of each book file, the name "ComBook" and a random identifier for your device, so it can tell your devices apart.
If you give a server a home network address, ComBook asks for local network access to reach it there.
These servers belong to you or to whoever runs them, and what they keep is up to them. I have no access to them.
iCloud
iCloud sync is off unless you turn it on. Then the books you imported and their reading state go into your own iCloud Drive, under your Apple Account, where Apple's privacy policy applies. I can't see any of it.
Purchases
ComBook Pro is bought through the App Store. Apple handles the payment, and the app checks on your device what your Apple Account owns. Apple gives me sales figures, not who bought.
Feedback and support
Settings → About → Send Feedback opens an email in your own mail app. It is filled in with the app version and how it was installed, your iOS version and device model, whether Pro is unlocked, which kinds of sources are connected and how many catalogs, the sync mode and the size of your library. It never contains a server address, username, password or key. You see the whole message and decide whether to send it.
I use emails only to answer you, and delete them once they are no longer needed. You can ask for a copy or for deletion at any time. The legal basis is answering your request (Art. 6(1)(b) and (f) GDPR).
Issues on the public tracker are public, and GitHub's privacy policy applies there.
Crash reports from Apple
If you allowed it in iOS Settings, under Privacy & Security → Analytics & Improvements → Share With App Developers, Apple may pass anonymous crash reports and usage statistics on to me. They identify no one, and I use them only to fix bugs. You can turn this off there at any time.
This website
combook.app sets no cookies, runs no analytics and loads nothing from other servers. The server it runs on keeps no access logs. Links to TestFlight, the App Store or GitHub take you to those services, under their own privacy policies.
Children
ComBook collects nothing from anyone, children included.
Your rights
Since I hold no data about you from the app, there is usually nothing to access, correct or delete. For anything you sent by email, write to [email protected]. Under the GDPR you can also complain to a data protection supervisory authority.
Changes
If this ever changes, for example when a feature arrives that runs on my own servers, this page will say so before that feature ships, and the date at the top will change.
Who is responsible
ComBook is made by one developer, Jackolix. Questions about privacy: [email protected].