Koodo Reader is an open-source e-book reader for organizing and reading digital books.

Koodo Reader is open source under the GNU AGPL v3, and its desktop version is free to use with an unlimited number of books. An optional Pro subscription costs $4.99 per year. Whether that cost is worthwhile depends on which features matter: the free reader covers local reading, library organization, bookmarks, notes, and highlights, while Pro adds syncing and several online tools.

What the free version provides

For a collection stored on a computer, Koodo Reader provides a reading interface with single-page, two-column, and continuous-scroll layouts. Readers can adjust fonts, spacing, margins, and colors, or switch to night mode. These controls make it possible to adapt the display to different books and reading conditions without changing the source files.

The program supports more than 15 formats, including EPUB, PDF, MOBI, AZW3, TXT, FB2, and CBZ/CBR comic archives. It is intended for DRM-free material; it can open DRM-free MOBI and AZW3 files but cannot read books protected by Amazon DRM. It also does not support DRM-protected books from stores or libraries.

Organizing a personal library

Books can be added by dragging files into the application, and whole folders can be batch-imported. Shelves provide a way to group and sort titles within the library. While reading, users can place bookmarks, highlight passages, add notes, and apply text styling. Those annotations are organized by book, which helps keep reading references connected to the relevant title.

The program is available for Windows, macOS, Linux, Android, iOS, and the web. On Windows, installation choices include an x64 installer as well as portable EXE and ZIP versions. Readers comparing platform use with a local-library workflow can review Koodo Reader when considering the key boundary: the free desktop library has no book-count limit, but cross-device syncing is not included without Pro.

What the Pro subscription changes

Pro adds synchronization of books, reading progress, and notes across devices through cloud storage or WebDAV. Supported services include OneDrive, Google Drive, and Dropbox, among others. It also enables importing books from cloud services, so users can bring files into their library without relying only on local folder imports.

Other Pro tools include the official translation and dictionary, AI reading assistance, natural text-to-speech voices, and OCR for scanned PDFs. These services are separate from the core reading controls and organization features, so the subscription is most relevant to readers who need them or want their library and annotations synchronized. A seven-day trial is optional.

Practical fit

Koodo Reader suits readers who keep a DRM-free collection and want one application for several common e-book and comic formats, with flexible display settings and per-book annotations. Its free desktop edition is sufficient for reading and managing a local library. Readers who require free synchronization between devices, or who rely on protected store and library books, will encounter limits that the paid plan does not remove.