Event Taps Testbench is a free utility for software developers. You can use it to explore what your applications can do with Quartz Event Taps. It is also a useful tool to test virtual software input devices, assistive applications for persons with disabilities, remote control software, and drivers for hardware input devices such as trackballs and tablets.
You can configure and install as many event taps as you like, and monitor user input events in real time. In addition you can configure how the event taps respond to user input, by performing the example actions provided, by blocking or modifying user input before the events are posted to their targets, and by posting additional events before and after the original event is posted.