FBReader vs MuPDF

FBReader is an ebook reader for Windows, macOS, Linux, Android, and iOS. It opens formats including ePub, fb2, mobi, HTML, RTF, and plain text, as well as ePub books protected with Readium LCP. Its Book Network can synchronize collections, reading positions, bookmarks, and custom shelves across supported devices. Books in the network are stored in the user's Google Drive space, while metadata, covers, and reading positions are stored on FBReader servers.

Online OPDS book catalogues are supported on Android, Windows, macOS, and Linux; iOS support is planned. Android Premium adds PDF and comics support, Google and DeepL translation integration, and automatic reading aloud. The free iOS version is limited to ten books and disables online translators. FBReader offers free plans for desktop, Android, and iOS; Android Premium is $14.99 as a one-time purchase. The company says its current code is closed source.

MuPDF is an embeddable SDK for developers working with PDFs and other document formats in desktop, cloud/server, or embedded projects. It supports viewing, editing, extracting, signing, rendering, redacting, annotating, splitting, merging, compressing, and converting documents. Listed inputs include PDF, ePUB, image formats, SVG, CBZ, and XPS; outputs include PDF, text, HTML, PostScript, print formats, PNG, SVG, and PNM/PAM. Developer bindings include MuPDF Core, PyMuPDF, MuPDF.js, and MuPDF.NET. The open-source release is AGPL-licensed, and embedding it in a product may require a commercial license. For server-based use of the open-source software, the licensing terms require disclosure of application source code to users interacting with it. Commercial licenses provide an alternative without AGPL code disclosure and include technical support and free upgrades. The Commercial plan is listed at $299 a month and includes one licensed domain and one preview domain for testing; a 14-day trial is also listed. Open-source users can seek community help through Discord and the bug tracker.