KyBook 3
KyBook 3 is an ebook reader and cataloging app for iOS, also listed for macOS.
What KyBook 3 is
KyBook 3 is an ebook reader and cataloging app for iOS, also listed for macOS. It supports DRM-free EPUB and PDF, MOBI, AZW3, DjVu, FictionBook files, comics, audiobooks, plain text, and rich text. Reading options include day, night, and sepia themes, several page-turn styles, auto scrolling, and text-to-speech. Readers can mark passages, add bookmarks, and draw annotations, then export annotations in Markdown, HTML, PDF, or RTF. The app connects to OPDS catalogs, provides a catalog list, and accepts user-added catalogs such as a Calibre content server. Files can be accessed through listed cloud services, SMB/CIFS shares, or WebDAV. It can also serve device files over Wi-Fi and stream audiobooks from cloud storage. The free download has in-app purchases. Synchronization requires a subscription, while listed Pro features require a one-time purchase. The maker specifies a 64-bit device and iOS 11 minimum; macOS use requires macOS 11 or later on an Apple M1 Mac.
Good
- Supports ebook, comic, audiobook, and text formats
- Offers annotation exports in four formats
- Connects to OPDS catalogs and multiple storage services
- Can stream audiobooks from cloud storage
Watch out
- Synchronization requires a subscription
- Pro mode features require an in-app purchase
- Requires a 64-bit device and iOS 11 minimum
Who it suits
KyBook 3 suits readers who want cataloging, multiple ebook and audiobook formats, annotations, and catalog or storage connections. Readers who need synchronization should note that it requires a subscription.
Verdict
KyBook 3 combines reading, cataloging, annotation, and storage features across supported Apple platforms. The free download is available, but synchronization and listed Pro capabilities require purchases.
Plans and prices
From KyBook 3's own pricing page, checked 15 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Free | Free | Reading and cataloguing; in-app purchases available |
| Upgrade to Pro (Discount) | $2.99, paid once | Discounted Pro upgrade |
| 3 months subscription | $4.49 a month | Synchronizes ebook metadata and files · Every 3 months; auto-renewing |
| Upgrade to Pro | $4.99, paid once | Pro features; batch OPDS downloads and batch metadata editing require Pro |
| Yearly subscription | $14.99 a year | Synchronizes ebook metadata and files · Every year; auto-renewing |
The facts
Each one read from KyBook 3's own pages, with the date it was checked.
What it does
- Annotations
- Readers can highlight, bookmark and draw annotations with Apple Pencil or touch, then export them as Markdown, HTML, PDF or RTF.checked 15 Oct 2026
- API and SDK
- The reviewed official pages describe no public KyBook API, SDK or developer integration interface.checked 15 Oct 2026
- Catalogs
- It supports OPDS catalogs, includes a list of known catalogs and allows users to add their own, such as a Calibre content server.checked 7 Oct 2026
- Content server
- A built-in content server exposes device files over Wi-Fi through a web browser.checked 15 Oct 2026
- Documentation
- The official help URL exists, while the public site repository provides feature pages and a dated changelog rather than an API manual.checked 15 Oct 2026
- Formats
- It supports EPUB, PDF, DjVu, MOBI/AZW3, FictionBook, comic book, audiobook, plain text and rich text formats.checked 7 Oct 2026
- Latest listed version
- The App Store lists version 0.7.8, released February 23, 2019.checked 15 Oct 2026
- Library organization
- Cataloguing supports categories, tags, collections, folder trees, flexible sorting and drag-and-drop shelf arrangement.checked 15 Oct 2026
- Licence
- The public KyBook GitHub repository lists README, screenshots and issues but no license file is shown in its repository file list.checked 15 Oct 2026
- Limit: interface and performance
- Independent reviewers mention a reading interface needing improvement, lag, awkward highlighting and subscription-gated features.checked 15 Oct 2026
- Limit: open issues
- The public issue tracker shows 461 open issues, including sync, registration, freezing, highlighting, text-to-speech and Calibre-server problems.checked 15 Oct 2026
- Limit: support responsiveness
- App Store reviews describe unanswered bug reports and certificate-related sync failures.checked 15 Oct 2026
- Limit: synchronization
- Reviewers report that cross-device synchronization and account creation often fail, including after paying for the subscription.checked 15 Oct 2026
- Limit: update stagnation
- Reviewers complain that the app has gone years without releases and fear it has been abandoned.checked 15 Oct 2026
- Metadata and contents
- KyBook extracts metadata automatically and lets users edit metadata and create or edit tables of contents.checked 15 Oct 2026
- Notable changelog
- The February 4, 2019 release fixed Chinese OCR language-pack downloading and reading-time calculation issues.checked 15 Oct 2026
- OPDS
- Users can browse built-in OPDS catalogs, add their own catalogs such as Calibre servers, and reach onion OPDS catalogs through Tor.checked 15 Oct 2026
- OPDS over Tor
- The maker's page says the app supports .onion OPDS catalogs reachable via the Tor Network.checked 7 Oct 2026
- Other capabilities
- The app can run a content server for accessing device files over Wi-Fi and supports streaming audiobooks from cloud storage.checked 7 Oct 2026
- PDF and DjVu tools
- PDF and DjVu support includes manual or automatic margin cropping, double-tap zoom, PDF reflow on iPhone and OCR.checked 15 Oct 2026
- Praise: customization
- JustUseApp reviewers repeatedly praise the large amount of customization and broad format support.checked 15 Oct 2026
The company
- Company identity
- The App Store identifies the seller and developer as Konstantin Bukreev.checked 15 Oct 2026
- Maker and seller
- The App Store identifies Konstantin Bukreev as the app's developer and seller.checked 7 Oct 2026
Where it runs
- Device requirements
- The maker's page says KyBook 3 requires a 64-bit device and iOS 11 minimum; the App Store lists iPhone and iPad compatibility and macOS 11 or later on an Apple M1 Mac.checked 7 Oct 2026
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