# KyBook 3 Ebook Reader — Epub, Mobi, Djvu and More

> E-book reader and cataloger supporting multiple formats, cloud storage, and annotations. (iPhone/iPad app by Konstantin Bukreev.)

- Source: https://appshunter.io/ios/app/kybook-3-ebook-reader/id1348198785 (this page in markdown: same URL + `.md`)
- Developer: [Konstantin Bukreev](https://appshunter.io/developer/547576207)
- Category: Books, Education
- Price: Free with in-app purchases
- Rating: 4.70/5 from 4,616 App Store ratings · 670 written reviews indexed
- Age rating: 17+
- Requires: iOS 11.0 · 53 MB
- Languages: American English, Czech, Russian, Chinese (Simplified, China), European Spanish
- Released: 2018-09-15
- Data updated: 2026-08-29
- Monetization: free with in-app purchases
- User reviews in markdown: https://appshunter.io/ios/app/kybook-3-ebook-reader/id1348198785/reviews.md

## What is KyBook 3 Ebook Reader?

KyBook is the application for reading and cataloging e-books in a modern, user-friendly style. 

KyBook supports all the major e-book formats, OPDS catalogs and Cloud Storage.

Key features
• All the major e-book formats
• OPDS catalogs
• Comfortable reading mode
• Powerful annotations
• Handy cataloguer
• Cloud Storage

Ebook Formats
• EPub (DRM-free)
• PDF (DRM-free)
• MobiPocket and Kindle (mobi, azw3)
• DjVu
• FictionBook (fb2, fb2.zip)
• Comic Book (cbr, cbz, cbt)
• Audio Book (mp3, m4a, m4b)
• Plain and rich text (txt, rtf)

OPDS Catalogs
• Provides access to enormous collection of free electronic books through OPDS-catalogs support.
• Built-in list of well-known OPDS Catalogs
• Allows add own catalog (e.g. Calibre content server)
• Supports for .onion OPDS Catalogs reachable via Tor Network

Comfortable reading mode
• Themes, color schemes for reading (day, night, sepia and more).
• Page turn with scroll, curl and slide.
• Designed to be fast, energy efficient, optimized for very large books (books in millions of words)
• Auto scrolling mode
• Text-to-speech technology to voice any e-book

EPUB/FB2/MOBI specific features
• Customizable font, text size, page margins, paragraph indentation, background and more
• Typography aware (hanging punctuation, hyphenations and more)

PDF/DJVU specific features
• Crops a page margins in manual and automatic mode
• Smart zooming by double-tap
• PDF Reflow on iPhone
• Page text recognition (OCR)

Powerful annotations
• Marked text and bookmarks
• Drawn annotations in any ebook (Apple Pencil support and just by touching).
• Annotations exports in Markdown, HTML, PDF, RTF formats.

Built-in the summary editor
• Markdown formatting.
• Exports summaries in Markdown, HTML, PDF, RTF formats.

Working with fragments of text
• Translation of separate words or complete sentences in different languages.
• Search for a word definition in dictionaries.
• Custom dictionaries in Dictd, StarDict and Lingvo DSL format
• Full text searching in a book (textual, fuzzy and search using regular expressions).
• Built-in search for a selected text on the Internet or Wikipedia.

Handy cataloguer
• Grouping by categories: by authors, subjects, sequences, publishers, tags, popular, recent, new, unread, reading and finished.
• Tags and collections to categorize ebooks.
• Search for books in the library and anywhere in the Internet.
• Own folders tree and flexible bookshelf settings for layout and sorting.
• Arranging books on a bookshelf by dragging.

Working with a metadata and a table of contents
• Automated extraction of a metadata from ebooks.
• Convenient editing of a metadata.
• Editing and creation (automatic or manual) of a table of contents.

File Storage
• Locally on the device.
• In the Cloud Storage (iCloud Drive, Google Drive, OneDrive, Dropbox, Yandex Disk).
• In the Local network on Shared Folders (SMB/CIFS) or on WebDAV server
• Transparent caching of books in the Internet or Local network.
• Supports of streaming audio books in Cloud Storage.
• Content Server for accessing files on the device via a WiFi.

Synchronization (requires subscription)
• Syncs all ebooks metadata and files.

KyBook offers the following subscriptions options:
• 3 months: 4.49 USD
• 1 year: 14.99 USD

Prices may vary in other countries respecting your local currency exchange rate. Your subscription will be charged to your iTunes account. At the end of the term, unless auto-renewables subscriptions are disabled, your subscription will automatically renew in your iTunes account. You will be charged for the regular price of your subscription within 24 hours prior to the end of the current term. You can turn off automatic renewal in your iTunes account settings at any time, but you must do so at least 24 hours before the end of the current term. Refunds will not be provided for the unused portion of any term.

Terms & Privacy policy 
    http://kybook-reader.com/terms
    http://kybook-reader.com/privacy-policy

## Key features

- Supports all major e-book formats
- OPDS catalog access
- Comfortable reading mode with themes
- Powerful annotations and summary editor
- Handy cataloguer with tagging
- Cloud storage integration

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Yearly subscription | $14.99 | per year |
| 3 months subscription | $4.49 | per 3 months |

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Upgrade to Pro | $4.99 | one-time |
| Upgrade to Pro (Discount) | $2.99 | one-time |


## What do users think of KyBook 3 Ebook Reader?

Overall sentiment: mixed

**Pros**

- 🚀 Excellent design, close to no ads
- 🚀 Handles various file formats well
- 👍 Customizable, lots of features
- 👍 Stable and fast
- 👍 Good for reading comics/manga
- 👍 Versatile, supports many features

**Cons**

- 🐛 Sync and account issues
- 🐛 Crashes, bugs, and compatibility problems
- 🔍 Confusing interface, hard to use
- 💰 Paid features and subscription model
- 🔍 Missing key features like page turn animation
- 🔍 Ads and monetization issues

**Commonly reported bugs**

- Inability to open/read certain file formats
- Sync and account creation issues
- Problems with PDF and image display
- Crashes and compatibility problems
- Duplication of books in library

**Most requested features**

- Left alignment option
- Dark mode/OLED black theme
- Improved image handling
- Better support for Chinese language
- Vertical page flip
- Improved text-to-speech capabilities

## Recent user reviews (10 of 670)

All indexed reviews: https://appshunter.io/ios/app/kybook-3-ebook-reader/id1348198785/reviews.md

### 5/5 — Only reader for me.

*2026-08-15, version v0.7.8*

This is the only reader I’ve found that allows you to organize your library by folders. If you don’t know. All you have to do is put ebook in a folder and KyBook reads the folder and creates a library based on folder name. Super easy. Super intuitive.

I REALLY HOPE that an update happens. I’d hate for this reader to die.

Still waiting on the next version.

### 5/5 — good

*2026-07-31, version v0.7.8*

very good

### 1/5 — Errors

*2026-07-31, version v0.7.8*

The KyBook e-reader error is caused by a critical issue: the developer has abandoned the app, and the SSL certificates for its sync servers have long since expired.
Since Apple's built-in mechanisms (iOS/iPadOS) strictly require a secure TLS connection, an outdated or missing certificate on the KyBook server reliably blocks authorization and syncing with error code -1200.

### 1/5 — Safety breach

*2026-07-31, version v0.7.8*

Crashes

### 4/5 — Pretty good

*2026-07-30, version v0.7.8*

The best reader for translating individual words and phrases that I’ve seen. But: selecting text is very annoying, eg it often selects blank spaces and dragging a selection field is unnecessarily difficult. That process needs an upgrade. I’d also like to be able to customize the popup menu.

### 5/5 — You can change text and background to any color!

*2026-07-26, version v0.7.8*

This is perfect for nighttime reading since you can can figure it to any color. 

I do dark red for the text and black for the background at night. 

During the day I do a Manila yellow background on black text. 

App is perfectly stable and works offline with ebook files and is free! 

Perfect app!

### 3/5 — Needs serious updating

*2026-07-20, version v0.7.8*

Great start! I use it as one of my primary readers.it finds books that sten’t in the newsgroups! But it needs work for stability and feature enhanent.

### 5/5 — Perfection

*2026-07-13, version v0.7.8*

This app is just perfect

### 5/5 — Great for free

*2026-06-21, version v0.7.8*

There’s some glitches, but it’s the best free text to speech reader I could find and it works great. Saves place in the book and the voices are as good as you can ask for for normal tts

### 1/5 — 簡体中国語がデフォ？

*2026-05-31*

さっぱりメニュー項目がわからないので使えない
せめて英語なら使えるのだが

## Frequently asked questions about KyBook 3 Ebook Reader

### What e-book formats does KyBook 3 support?

KyBook 3 supports a wide array of e-book formats including EPUB (DRM-free), PDF (DRM-free), MobiPocket and Kindle (mobi, azw3), DjVu, FictionBook (fb2, fb2.zip), Comic Book (cbr, cbz, cbt), Audio Book (mp3, m4a, m4b), and plain/rich text (txt, rtf).

### How can I organize my e-book library with KyBook 3?

The app features a handy cataloguer that allows you to group books by authors, subjects, sequences, publishers, tags, and more. You can also use tags and collections to categorize your ebooks, and arrange them on a bookshelf with flexible layout and sorting options.

### Is KyBook 3 free to use?

The application is free to download and use, offering core reading and cataloging functionalities. Additional features or advanced capabilities may be available through in-app purchases.

### Can I read books from cloud storage services?

Yes, KyBook 3 seamlessly integrates with popular cloud storage services such as iCloud Drive, Google Drive, OneDrive, Dropbox, and Yandex Disk. It also supports local network storage via Shared Folders (SMB/CIFS) or WebDAV servers.

### What are the annotation features in KyBook 3?

KyBook 3 offers powerful annotation tools, allowing you to mark text, add bookmarks, and even draw directly on any ebook, with support for Apple Pencil. These annotations can be exported in various formats like Markdown, HTML, PDF, and RTF.

## Version history (last 5 releases)

### v0.7.8 — 2019-02-23

- Fixed the issue with clipped text in PDF Reflow.
- Added the ability to change text size in PDF Reflow mode.
- PDF page is rendered in the current theme when the PDF Reflow mode is on.
- The application now remembers the Reflow mode for the recent open PDF book.
- Various minor improvements and bugfixes.

### v0.7.6 — 2019-02-15

- Updated the Spanish localization.
- Added the support of migration from KyBook 1 (requires KyBook 1 v2.1.8 and above).
- Various minor improvements and bugfixes.

### v0.7.5 — 2019-02-04

- Fixed the issue with downloading language pack for recognition (OCR) books in Chinese.
- Fixed the bug with incorrect calculation of the reading time when the book is not active.
- Various minor improvements and bugfixes.

### v0.7.4 — 2019-01-30

- Added the Fast selection feature in the Reader.
- Removed support of 3D Touch in the Reader.
- Added OCR function for DjVu and PDF pages without text layer.
- When adding a bookmark, the title of the chapter is added to the text.
- Removed default paragraph indent from EPub, Mobi, FB2 display styles.

### v0.7.3 — 2019-01-22

- Fixed the issue with resetting playback speed in audiobooks after paused.
- Fixed the issue with turning pages in landscape orientation using a hardware keyboard.
- Few small improvements.

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## More apps by Konstantin Bukreev

- [KyBook - EPub,FB2,PDF,DjVu Reader](https://appshunter.io/ios/app/kybook-epubfb2pdfdjvu-reader/id673027171)
- [KyBook 2 Ebook Reader](https://appshunter.io/ios/app/kybook-2-ebook-reader/id1018584176)
- [BiLibre DjVu and PDF Reader](https://appshunter.io/ios/app/bilibre-djvu-and-pdf-reader/id1230039040)

All apps by Konstantin Bukreev: https://appshunter.io/developer/547576207

## Related topics

[kybook3](https://appshunter.io/ios/topics/kybook3) · [kybook](https://appshunter.io/ios/topics/kybook) · [kybook 3 ebook reader](https://appshunter.io/ios/topics/kybook-3-ebook-reader) · [m4 reader](https://appshunter.io/ios/topics/m4-reader) · [azw3 reader](https://appshunter.io/ios/topics/azw3-reader) · [mobi reader ebook](https://appshunter.io/ios/topics/mobi-reader-ebook) · [kbook](https://appshunter.io/ios/topics/kbook) · [kybook 2 ebook reader](https://appshunter.io/ios/topics/kybook-2-ebook-reader) · [azw3](https://appshunter.io/ios/topics/azw3) · [mobi reader](https://appshunter.io/ios/topics/mobi-reader) · [ebook applications](https://appshunter.io/ios/topics/ebook-applications) · [djvu reader](https://appshunter.io/ios/topics/djvu-reader) · [opds](https://appshunter.io/ios/topics/opds) · [mapleread](https://appshunter.io/ios/topics/mapleread) · [libre 3 reader](https://appshunter.io/ios/topics/libre-3-reader) · [yomu ebook reader](https://appshunter.io/ios/topics/yomu-ebook-reader) · [mobyx](https://appshunter.io/ios/topics/mobyx) · [mobi reader pdf](https://appshunter.io/ios/topics/mobi-reader-pdf) · [calibre companion](https://appshunter.io/ios/topics/calibre-companion) · [usb reader media](https://appshunter.io/ios/topics/usb-reader-media)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-29.*