You’ll find lots of ebooks online that you can buy or download for free, but if you don’t have a dedicated eReader, how can you read them? Fire up an ebook reader app on your phone or tablet. Whether you have Mobi, EPUB, or PDF files, there is an eReader app that will work for you. In this list, we have listed down 23 of the best open source ebook reader apps, softwares and tools. Open source simply means the source code of the app is provided. Read on for your best options.
Calibre
Linux, MacOS and Windows
GPL-3.0 License / Source Files
Calibre is an e-book manager. It can view, convert, edit and catalog e-books in all of the major e-book formats. It can also talk to e-book reader devices. It can go out to the internet and fetch metadata for your books. It can download newspapers and convert them into e-books for convenient reading.
KOReader
Android, Cervantes, Kindle, Kobo, Linux, Pocketbook, reMarkable
AGPL-3.0 License / Source Files
An ebook reader application supporting PDF, DjVu, EPUB, FB2 and many more formats, running on Cervantes, Kindle, Kobo, PocketBook and Android devices.
Polar Bookshelf
Linux, MacOS and Windows
GPL-3.0 License / Source Files
Polar is personal knowledge repository which supports advanced features like incremental reading, annotation, comments, and spaced repetition. It supports reading PDF, EPUB, and the web content.
Foliate
Linux
A simple and modern eBook viewer for Linux desktops.