Xdebug

Xdebug is a PHP extension that provides debugging and profiling capabilities. It's a powerful tool that can help you understand what your code is doing, track down bugs, and optimize performance. With Xdebug, you can set breakpoints, watch variables, and step through your code one line at a time. For instance, to start using Xdebug, you first need to install it and then initialize it in your code like so:

<?php

xdebug_start_trace();

// Your code here...

xdebug_stop_trace();
?>

Xdebug can significantly speed up bug-tracking and testing, making it an essential tool in any PHP developer's toolkit.