Sites and apps similar to Flow include calibre, which is free and open source. Other options are SumatraPDF, Readest, KOReader and Koodo Reader. Ebook Readers like Flow are a crowded field, with more than 50 alternatives for Android, Windows, Linux, Mac and iPad.
Free e-book manager with features including library management, format conversion, syncing to devices, internet-independent operation, built-in viewer, news download as e-books, text-to-speech, privacy focus, extensible plugins, and no registration or tracking.
India
This free, open-source viewer for Windows supports multiple formats like PDF, eBooks (ePub, Mobi), CHM, and Comic Books (CBZ, CBR). Prioritizing simplicity and speed, it offers a lightweight, portable design with a minimalist interface, catering to users seeking fast and efficient document viewing.
Poland
EU
Readest is a modern, open-source ebook reader for Windows, macOS, Linux, iOS, Android, and the web.
United States
An ebook reader application supporting PDF, DjVu, EPUB, FB2 and many more formats, running on Kindle, Kobo, PocketBook, Linux and Android devices.
Koodo Reader is a powerful ebook reader designed to provide a simple and easy-to-use reading experience.
China
MuPDF offers a highly versatile PDF, XPS, and eBook interpreter, customizable as a renderer, viewer, or toolkit. Features include digital signatures, redactions, form filling, annotations, and page manipulation, ideal for mobile, eBooks, and embedded apps supporting Java, C++, and Python.
United States
Librera Reader is a highly customizable and feature-rich application for reading books in PDF, EPUB, MOBI, DjVu, FB2, TXT, RTF, AZW, AZW3, HTML, CBZ, CBR formats on Android devices.
SlovakiaEU
ItalyEU
The Kindle app puts millions of books, magazines, newspapers, comics, and manga at your fingertips.
United States
Russia
Openlib is an open source app to download and read books from shadow library (Anna’s Archive). The App Has Built In Reader to Read Books.
Episteme Reader is an offline-first application designed for reading various document formats. It leverages native Android technologies and C++ libraries to provide a performant reading experience with customization capabilities.
India
