# KOReader **KOReader replaces the stock software on your e-reader with something you actually control.** It runs on Kindle, Kobo, PocketBook, Cervantes, reMarkable, Android, Linux and macOS. AGPL-3.0, and old enough now to be boring in the good way. The pitch is simple. Manufacturer readers lock you into their format and their store. KOReader reads EPUB, PDF, DjVu, FB2, Mobi, DOC, RTF, HTML, CHM, TXT, CBZ and CBT, plus scanned documents reflowed through k2pdfopt. You get the fonts, margins, line spacing and hyphenation you want instead of the three presets Amazon decided on. ## Why people switch - **Speed.** The most repeated comment from users is that it's noticeably faster than stock Kindle and Kobo firmware on the same hardware. - **PDF that doesn't hurt.** Semi-automatic cropping makes academic papers readable on a 6" screen, which is the thing stock readers are worst at. - **Lookups without leaving the page.** StarDict dictionaries, [[Wikipedia]], and Google Translate are built in. - **It talks to your stuff.** Calibre, Wallabag, OPDS catalogues, RSS, plus a sync server for reading position across devices. There's a plugin that pushes highlights to [[Readwise]]. - **A plugin ecosystem**, including LLM integrations and library management add-ons. ## The catch The UI is the recurring complaint, and it's fair. Settings are buried across nested menus and finding the one you want is trial and error the first few times. The community answer is UI plugins (SimpleUI, Zen UI, Bookshelf) rather than a fix upstream. Some Kobo owners also report worse battery life than stock. So budget an evening for configuration. After that it mostly disappears, which is what you want from a reading app. ## Related - [[Open Source]] - [[Benefits of taking notes while reading]] - [[Readwise]] - [[Wikipedia]] ## References - Source code: https://github.com/koreader/koreader - Hacker News discussion: https://news.ycombinator.com/item?id=49095865