KOReader
KOReader is an open-source document reader optimized for e-ink devices, with support for Kindle, Kobo, PocketBook, reMarkable, Android and Linux plus PDF reflow and many formats.
What KOReader is for
KOReader is designed for PDFs, DjVu, EPUB, FB2, MOBI, comic archives and other documents on e-ink readers, Android and Linux. Its cropping, columns, reflow, dictionaries, annotations and refresh strategies are especially useful for scanned documents and low-refresh screens. It is not an e-book store and does not bypass DRM.
Version and device differences
Version 2026.07.1 includes builds for several Android architectures, Linux, Kindle, Kobo, PocketBook and reMarkable. Similar device names do not make packages interchangeable: model, architecture, firmware and launcher behavior determine the valid installation path. Keep an official recovery method and a system backup before touching a dedicated reader.
Network and device security
KOReader can connect to Calibre, OPDS, Wallabag, WebDAV, FTP, SSH and other services, and can export annotations and reading data. Each service expands the network and credential boundary. In particular, an SSH service without a password can expose a reader to other devices on the same network; use strong authentication, limited scope and trusted networks.
Maintenance note
This page was reviewed on 2026-08-23 against KOReader 2026.07.1, supported devices and formats, PDF reflow, transfer methods, SSH boundaries and AGPLv3 licensing.
Save to your cloud drive
Open the cloud drive to get the file directly, or save it for convenient access on another device.
Quark Cloud Drive
RecommendedSave KOReader to this cloud drive
Baidu Netdisk
Save KOReader to this cloud drive
KOReader device installation, PDF reflow and annotation backup
Confirm the device and firmware first, then install the matching build, import test documents, configure PDF or EPUB reading, transfer books and back up annotations.
Before you start
- Record the exact device model, architecture, firmware version and current boot state, and back up an e-ink reader before changing it.
- Use unencrypted documents that you are entitled to read, and avoid the only copy of an important library for the first test.
- Use only installation steps matching the model and firmware. Keep a supported recovery path for a dedicated reader.
Installation steps
- 01
Choose the device build
Select an ARM, ARM64 or x86 APK for Android, a matching AppImage, DEB or archive for Linux, or the package specific to the dedicated reader. Do not interchange ZIPs between devices.
- 02
Install in a recoverable state
Charge the device, pause unstable sync jobs, back up the original system and library, and confirm that the firmware supports the selected build.
- 03
Limit network services
Enable OPDS, WebDAV, FTP, SSH or SFTP only when needed. Use strong authentication and a trusted network for SSH, and keep a passwordless service away from public networks.
Quick start
- 01
Import EPUB and PDF fixtures
Open one reflowable EPUB and one fixed PDF, checking table of contents, fonts, images, page turns and sleep recovery before adding a full library.
- 02
Configure PDF cropping and reflow
Crop margins first, then try zoom, columns and reflow. For a poor scan, lower expectations and do not treat OCR output as authoritative text without checking the page.
- 03
Create and back up annotations
Add bookmarks, highlights and notes, export or copy the data outside the device, reopen the document to verify locations and only then batch-import the library.
Usage tips
- E-ink refresh strategy affects ghosting, speed and battery use; animation, scrolling and frequent refreshes vary by device.
- Calibre, OPDS, Wallabag, dictionaries, translation and cloud storage are separate services with their own credentials and privacy terms.
- Firmware upgrades can change third-party launch behavior, so keep recovery files and recheck device support before upgrading.
Troubleshooting and uninstall
Why is there no KOReader entry after installation?
Do not copy random packages repeatedly. Recheck model, firmware, directory structure and launcher requirements, verify file integrity and return to the known recovery path if the device behaves abnormally.
Why is a large PDF slow or out of memory?
Reduce OCR, reflow and high-quality rendering, lower cache settings or split a legal personal document copy by chapter. Older hardware limits cannot be solved by increasing cache alone.
- Export annotations and settingsSave bookmarks, highlights, notes, dictionaries, fonts and network settings, checking that backups do not contain unencrypted passwords.
- Use the device-supported removal pathRemove the application normally on Android or Linux. On a dedicated reader, follow its matching recovery or uninstall instructions and confirm the system still boots before deleting backups.
Frequently asked questions
Can KOReader install directly on every Kindle or Kobo?
No. Android and general Linux installs are more direct, while Kindle and Kobo require a model- and firmware-specific path and sometimes third-party software support. A mismatch can affect boot, updates or warranty.
Can a scanned PDF change font size like an EPUB?
Not in the same way. A scan is mostly an image; cropping, zoom, reflow and OCR can help, but results depend on page quality. Reflowable EPUB handles font and line spacing more consistently.
Does KOReader support DRM-protected books?
It is not a tool for bypassing DRM. Use unencrypted files or files you have lawful reading access to, and keep protected books in the supported reader supplied by their distributor.
Does the download require an extraction code?
The Quark entry does not require one; the four-character code for the Baidu entry is shown beside its download entry.