MuPDF is a free and open-source software framework written in C that implements a PDF, XPS, and EPUB parsing and rendering engine. It is used primarily to render pages into bitmaps, but also provides support for other operations such as searching and listing the table of contents and hyperlinks. Developed by Artifex Software, Inc.
License: Open Source
MuPDF is a lightweight PDF viewer with advanced text rendering and developer-friendly features, while RepliGo Reader is more focused on providing a rich user experience with robust annotation and form-filling capabilities. The choice between them depends on whether the user prioritizes performance and simplicity (MuPDF) or feature richness and usability (RepliGo Reader).