GazeFlow Webcam Eye Tracking engine
Try Cross-platform GazeFlow Live Demo: https://test.gazerecorder.tk/
GazeFlow API : https://github.com/szydej/GazeFlowAPI
An accuracy and comparison test showed that GazeFlow’s accuracy measurements (< 0.9˚-1.0˚) are, higher than the desired level of accuracy indicated by literature, especially when the head is allowed to move freely. These measurements are however comparable to the accuracy measurements of the compared eye tracking device using infrared light (SMI Red 250).
The full report can be found here
The different heatmaps generated by both eye trackers can be found here