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For detailed instructions and more information about using Event Taps Testbench, launch Event Taps Testbench and choose Help > Event Taps Testbench Help. If you have questions that aren't answered in the Help book or on this website, send email to us at

Visit PFiddlesoft Frameworks Downloads to download the source code for Event Taps Testbench, to serve as example code showing how to use the PFEventTaps Framework.

A Note on Security

When you click the Add button in Event Taps Testbench's main window and an untitled Event Tap window opens, you see a number of checkboxes on the left that you can select to specify the events you want to tap, such as Left Mouse Down and Mouse Moved. Two of these events, Key Down and Key Up, are marked "requires access." Starting with macOS Mojave 10.14, the Active Filter radio button on the right is also marked "requires access." These controls are disabled if access has not been authorized.

Prior to Mojave, macOS allowed users to install event taps that tap all events other than the Key Down and Key Up events without granting access to the application to monitor or control the computer using Accessibility features. Despite this, if access has not yet been granted to Event Taps Testbench, it always presents an alert at launch asking the user to grant access in advance. This is done simply as a convenience, to allow the user to get on with testing Quartz Event Taps without worrying about what kind of event will be tapped. If the user knows that the Key Down and Key Up events would not be involved in the current work session, access could be denied and Event Taps Testbench would still work. Only the Key Down and Key Up checkboxes would be disabled.

Starting with Mojave, Apple's implementation of additional security features includes a requirement that users grant an application like Event Taps Testbench access to monitor or control the computer using accessibility features for event taps of all kinds that are not "Passive Listener" taps but are instead "Active Filter" taps. A user can no longer install Active Filter event taps of any kind, nor Passive Filter event taps for Key Down and Key Up events, unless access has been granted.