PyeLink and SyeLink: Open-source Python tools for low-level EyeLink experiment control and data parsing
Mohammadhossein Salari, Marcus Nyström, Diederick Christian Niehorster, Roman Bednarik · 2026
We present PyeLink and SyeLink, two complementary open-source Python tools for running eye-tracking experiments and parsing data from SR Research Ltd. EyeLink eye tracking hardware. PyeLink simplifies experiment creation through plug-and-play support for multiple display backends (Pygame, PsychoPy, Pyglet) while enabling two features not available in existing tools: recording data during calibration and validation phases, and simultaneously recording raw P-CR data alongside calibrated gaze data. These enriched data files cannot be processed by existing parsers, which motivated the development of SyeLink. SyeLink parser processes recorded files and makes the data accessible through both Python API and command-line interface. SyeLink converts raw ASC data into structured JSON and CSV formats and supports visualization of calibration and validation results. Together, these tools provide a complete Python workflow for running eye-tracking experiments with enriched data recording capabilities while exposing all configurable aspects of EyeLink eye trackers.