Sioyek is a PDF viewer designed for reading research papers and technical books.
It’s notable for its keyboard-based navigation.
This is free and open source software.
Features include:
- Quick Open – search and open files.
- Overview – obtain a quick overview of links, references and citations (works even when the document doesn’t provide links).
- Table of Contents with the ability to search and jump to entries.
- Smart Jump – jump to any referenced figure or bibliography item even if the PDF file doesn’t provide links.
- Mark – named locations within a PDF file (each mark has a single character name for example ‘a’ or ‘m’) which you can quickly jump to using their name.
- Bookmarks – similar to marks except they are named by a text string and they are all global
- Highlights – highlight text and search within the highlighted text.
- Portals – link the paragraph’s location to the figure’s location.
- Highly customizable.
- Cross-platform support – runs under Linux, macOS, and Windows.
Website: sioyek.info
Support: Documentation, GitHub Code Repository
Developer: A Mostafavi
License: GNU General Public License v3.0

Sioyek is written in C. Learn C with our recommended free books and free tutorials.
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