What is KOReader used for?

KOReader is an open-source document and ebook reader for e-ink devices, Android and Linux that supports PDF, DjVu, EPUB and many other formats. It is a good fit for reading ebooks on a jailbroken Kindle or Kobo and replacing a stock e-reader reading app.

Is KOReader open source?

Yes. KOReader is open source under the AGPL-3.0 licence. Its source code is on GitHub at koreader/koreader and is written mainly in Lua.

Yes. KOReader is open source, so the software itself is free to use.

Can I self-host KOReader?

Yes. KOReader can be self-hosted on your own server or infrastructure; there is no official hosted version.

What is KOReader an alternative to?

KOReader is an open-source alternative to Kobo. Other open-source alternatives to Kobo include calibre, Foliate and Calibre-Web.

Is KOReader actively maintained?

Yes. The most recent commit to KOReader was on 2 October 2026, and the latest release is v2026.07.1, published on 1 August 2026. The project has 30k stars on GitHub.

KOReader: open-source alternative to Kobo

About KOReader

KOReader is a document viewer aimed mainly at e-ink readers. It runs on Cervantes, Kindle, Kobo, PocketBook and reMarkable devices as well as Android and Linux computers, and developers can use an emulator on Linux and macOS. The project is written largely in Lua with LuaJIT and is released under the AGPL-3.0 license.

It handles fixed-page formats such as PDF, DjVu, CBZ and CBT, and reflowable formats including EPUB, FB2, Mobi, DOC, RTF, HTML, CHM and TXT. Scanned PDF and DjVu files can be reflowed with the bundled K2pdfopt library. Readers get customizable typesetting with arbitrary margins, line spacing, external fonts and hyphenation dictionaries. Integrations cover calibre, OPDS catalogs, Wallabag, Wikipedia and StarDict dictionaries, and the interface is tuned for e-ink with no animation and adjustable contrast. Plugins add further functionality.

Key features

PDF, DjVu, EPUB, FB2 and CBZ support
Reflow for scanned PDF and DjVu files
Custom margins, fonts and line spacing
calibre, OPDS and Wallabag integration
E-ink friendly interface without animation
Plugin system for extensions

Good fit for

→Reading ebooks on a jailbroken Kindle or Kobo
→Replacing a stock e-reader reading app

Built with: Lua
Tags: ebook-reader; e-ink; epub; pdf; djvu; kindle; kobo; lua

KOReader: questions and answers

What is KOReader used for?: KOReader is an open-source document and ebook reader for e-ink devices, Android and Linux that supports PDF, DjVu, EPUB and many other formats. It is a good fit for reading ebooks on a jailbroken Kindle or Kobo and replacing a stock e-reader reading app.
Is KOReader open source?: Yes. KOReader is open source under the AGPL-3.0 licence. Its source code is on GitHub at koreader/koreader and is written mainly in Lua.
Is KOReader free?: Yes. KOReader is open source, so the software itself is free to use.
Can I self-host KOReader?: Yes. KOReader can be self-hosted on your own server or infrastructure; there is no official hosted version.
What is KOReader an alternative to?: KOReader is an open-source alternative to Kobo. Other open-source alternatives to Kobo include calibre, Foliate and Calibre-Web.
Is KOReader actively maintained?: Yes. The most recent commit to KOReader was on 2 October 2026, and the latest release is v2026.07.1, published on 1 August 2026. The project has 30k stars on GitHub.