Open-source ebook readers

6 ebook readers whose code is public under an OSI-approved license, rated for privacy with evidence. Picks first, then by score.

1. Foliate Grade B

   Open-source e-book reader for Linux built with GTK, supporting EPUB, MOBI, AZW3, FB2, CBZ and PDF.

   Licensed under GPL-3.0. Source code

2. KOReader Grade B

   Open-source document and e-book reader for E Ink devices such as Kindle, Kobo and PocketBook, also available for Android and Linux. Supports EPUB, PDF, DjVu, CBZ and more.

   Licensed under AGPL-3.0. Source code

3. Calibre Grade D

   Free and open-source e-book manager for organizing, converting and reading e-books, with a built-in viewer, editor and device syncing.

   Licensed under GPL-3.0. Source code

4. Readest Grade D

   Open-source e-book reader for desktop, mobile and web, with optional cloud sync of books, progress and notes.

   Licensed under AGPL-3.0. Source code

5. Thorium Reader Grade D

   Open-source desktop reader for EPUB, PDF, audiobooks and comics from EDRLab, a French nonprofit. It supports LCP-protected library loans, read aloud and screen readers.

   Licensed under BSD-3-Clause. Source code

6. Librera Reader Grade F

   Open-source Android reader for EPUB, PDF, DjVu, MOBI, FB2 and other formats. A free ad-supported version, a paid PRO version and an F-Droid build are available.

   Licensed under GPL-3.0 or later. Source code

Compare all 10 ebook readers, open source or not.