Sioyek is a PDF viewer with a focus on textbooks and research papers

Original Article ↗ Hacker News Discussion ↗

A specialized PDF reader called Sioyek is drawing interest for its research-focused features such as vim-style keyboard navigation, autogenerated tables of contents, advanced highlighting modes, and tools for quickly jumping between citations, figures, and references. Commenters compare it to alternatives on iPad and desktop, and to broader knowledge-management stacks like Zotero, Obsidian, and newer apps that link annotations to notes, while also noting pain points such as extension complexity, bugs, and limited mobile support. The project appears actively developed on a separate branch, with work underway on multi-panel views, better extension support, and Android/iOS ports, reflecting wider demand for more powerful, cross-platform workflows for reading and annotating academic PDFs.

Overall reception

  • Many commenters are enthusiastic; several call Sioyek their primary or “best” PDF viewer for research.
  • Appreciated especially by users who like keyboard- and Vim-style navigation and research-focused workflows.
  • Some users still prefer other tools due to bugs, missing features, or ecosystem fit.

Notable features

  • Vim-like navigation (gg/G, command palette) and command-based UI are widely praised.
  • Visual line-highlighting (“visual mark” / ruler) and dark/solarized modes are cited as major reductions in eye strain.
  • Heuristic table-of-contents generation for PDFs without TOC is considered useful, though more reliable for papers than math-heavy textbooks.
  • Separate storage of annotations is seen as beneficial by some (clean PDFs, potential for standardized annotation formats), with an option to embed annotations into a new PDF.

Limitations and pain points

  • Plugin/extension installation is described as complex; some features (e.g., two-column viewing) were originally only via extensions.
  • Some users report crashes or inability to open multiple PDFs easily; others say recent versions mitigate this via settings/flags.
  • No bulk import or robust “open directory” handling, especially for large collections or cloud drives.
  • Windows 7 is not supported, which caused confusion about system requirements.
  • Some find the lack of traditional menus/help screens inconvenient.

Development status and roadmap

  • Initial concern about abandonment is countered by multiple references to an active development branch and even a private branch.
  • Newer/coming features (mostly in development): native two-panel and 2-page modes, simpler JavaScript extensions, possible ~/.config support, multi-window support, Android port; iOS port is reportedly more difficult.

Annotations, notes, and ecosystem integration

  • Debate over embedding annotations vs. external files; some want both for interoperability with other viewers and tools (Zotero, Obsidian, KOReader).
  • Broader discussion of research workflows: desire to integrate reading, annotation, note-taking, and long-term knowledge management without lock-in.
  • Several external tools are mentioned (knowledge bases, web annotation, collaborative readers) as complementary or aspirational integrations.

Mobile, e‑ink, and alternatives

  • Thread includes many recommendations for iPad and mobile PDF readers and e‑ink devices, reflecting a strong demand for Sioyek-like features on tablets.
  • Readers want features like single-column reflow, LLM-based semantic search, multi-format support, and easy export of highlights (e.g., to markdown).