The best open source alternative to Okular is SumatraPDF. If that doesn't suit you, our users have ranked more than 100 alternatives to Okular and loads of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Okular are PdfCraft, LibreOffice - Draw, KOReader and Koodo Reader.
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
Read, organize, combine, split and secure PDFs in a fast, native app written in Rust from the ground up. No account, no telemetry, no cloud.
United States
Draw lets you produce anything from a quick sketch to a complex plan, and gives you the means to communicate with graphics and diagrams. With a maximum page size of 300cm by 300cm, Draw is a an excellent package for producing technical drawings, general posters, and much else.
GermanyEU
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
Supports viewing and editing PDF annotations, displays multiple formats such as PDF, Postscript, DjVu, comic books, TIFF, DVI, XPS, remembers per-document zoom and position, features search, table-of-contents navigation, SyncTeX integration, and printing.
United States
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
ItalyEU
PDF Viewer (aka pdf.js) is a new revolutionary extension using web standard technologies that allows you to display within Mozilla Firefox almost all PDF files found on the web without a plugin.
United States
High-performance viewer for documents and images offering split tabs, customizable single or book layouts, portals for side-by-side sections, instant search, line highlight, annotation tools, link hints, searchable highlights, session management, and TOML config.
SpainEU
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
