Pablo Viquez has a new post to his site today showing you how to debug your PHP code with the help of JMeter (an Apache project) that tests functional behavior and performance and the Zend Debugger.

Now, I think JMeter is awesome, no doubt about it, however what if I want to test something while developing a new API Endpoint? well I used to be accustom to the nasty var_dump(); exit; combination or if the API was already completed I used to do error_log() everywhere and figure out the results. [...] I love the easy integration that Zend Server has with Zend Studio for debugging and I though to myself, why not just change the client that triggers the debugging console so instead of the browser use JMeter, at the end both uses HTTP so it should work, well guess what, IT DOES, and It's awesome. No more print_r, error_log, var_dump in the API, lets do the Step by Step debugging with JMeter!

He walks you through the steps needed to get it all set up and working together, complete with screenshots. Really, you can use whatever debugger setup you prefer (with something like Xdebug) and have jMeter execute on top of that - there's no interface directly between the debugger and jMeter.