Sioyek

What is Sioyek?

Sioyek is a free, open-source PDF reader designed for power users who work with large documents such as textbooks, academic papers, and technical manuals. It ships native installers for Windows, macOS, and Linux, and is built on top of the MuPDF rendering engine for fast page loading even on hundreds-of-megabytes PDFs.

Key features

• Smart navigation: a Quick Open dialog lets you search every PDF you have previously opened by title or path; a Table of Contents viewer jumps to any section.
• Smart Jump: click on a figure or in-text reference and Sioyek jumps to the referenced item even if the PDF does not contain internal links.
• Marks and bookmarks: vim-style single-character marks (local and global) and named bookmarks for quickly returning to a page.
• Highlights, annotations, and an overview panel that lists all figures, references, and tables in a document.
• Portals: pin two views of a document side-by-side, ideal for multi-monitor reading.
• Port-friendly installer with no telemetry, ads, or required account.

Comparison to paid PDF software

Compared to Adobe Acrobat Reader, Foxit Reader, and Nitro PDF, Sioyek launches far faster, ships a much smaller footprint, and stays out of your way with a keyboard-driven UI inspired by vi. Unlike Adobe Acrobat Reader, which nudges users toward cloud storage and paid features on every launch, Sioyek does not bundle any upsell, nor does it phone home. Its research-focused features (Smart Jump, Overview, bibliography lookup) are unique among free readers and are aimed squarely at students, academics, and engineers.