Sioyek is an open-source, cross-platform PDF viewer, optimized for research papers and textbooks. These are the release notes for the recently released sioyek 2.0. If you are not familiar with sioyek, here is a video tutorial.


We now have a super_fast_search option which can be enabled in prefs_user.config like so:

super_fast_search 1

When enabled, sioyek indexes document texts for extremely fast search:

For a more thorough benchmark and comparison with other viewers see this blog post.

The reasons that it is not enabled by default is that the index slightly increases memory usage (about 50MB for every 1000 pages). It should not be a big deal for most users though, so I recommend enabling it unless you have <2GB RAM.

When super_fast_search is enabled, we have a regex_search command which uses regular expressions to search the document. For example searching for [0-9] finds all the digits in the document.

Scrolling between pages in overview window

Sioyek allows you to open a quick overview of references (even when they are not linked in the PDF file). Previously you could scroll in this window but only in the original page. Now, we allow you to scroll to other pages in the overview window:

Search results in an overview

Using overview_next_item and overview_prev_item commands, you can now open an overview to search results instead of jumping to them:


Added a new overview_to_portal command which opens a quick overview to the closest portal. Previously portals were mostly useful for users with multiple monitors, but now they should be beneficial for all users. See the portal section of tutorial video for a brief introduction to what portals are, as well as a demo of this feature.


You can now define macros in your prefs_user.config file, which can be used to execute multiple commands. For example:

new_macro _goto_top_right goto_top_of_page;goto_right

Note that macro names must start with an underscore so as not to be confused with built-in sioyek commands. The commands in the list are separated using a semicolon.

Source other config files

Added a source command which allows you to include another config file in your prefs_user.config. Can be used like this:

source /path/to/other/file.config

Which is quite useful for easier installation of extensions and themes. For example see the dracula theme here:

Improved extensions

The official python module now uses a much faster communication method with the running sioyek process. Moreover, we have added some new variables which can be used in extensions, for example %{selection_begin_document} and %{selection_end_document} which expand to the current selection locations, and %{selected_rect} which expands to the current selected rectanle using the new select_rect command.

For example here is an extension that uses these new options to add text annotations to sioyek:

Other changes

  • Upgrade to MuPDF 1.20 .
  • New keybind parsing method with support for non-standard layouts and unicode characters
  • Add a smooth scroll mode.
  • Add ability to select single words using keyboard_select command
  • Add a scrollbar which can be enabled using toggle_scrollbar command
  • Add commands to set configuration options at runtime.
  • Add prerendered_page_count option which allows to configure how many pages does sioyek prerender
  • Add an option to show the closest bookmark in the statusbar
  • Add an option to indicate whether we are close to a portal in the statusbar
  • Add an option to highlight using middle click instead of pressing a button. See
  • Add ability to specify colors in config files using hexadecimal strings. For example instead of 1 1 0 you can now use #ffff00.
  • Many bug-fixes and quality of life improvements