Xdebug is probably the most popular PHP debugger and profiler out there.
Installing and Configuring Xdebug
If you haven't installed it yet
pecl install xdebug
Verify your installation with
php -i | grep xdebug
Locate where's your
php -i | grep php.ini
Enable Xdebug remote control by apending to the
php.ini file the next line
Open the Debug Edit Configurations window then Run > Debug…
Click on Add New Configuration, select PHP Remote Debug, on the Configuration section click on the Servers select and create a new one. Fill the host to the application you want to debug, usually "localhost", the port and set the debugger to Xdebug. Once the server is added and back in the Configuration section, set the Ide key (session id) to your username. If you don't know, open a console and execute
Create the new configuration. Now you'll have a new option to debug under the Run menu. Execute your PHP application, and back in PHPStorm select Run > Debug 'Your new configuration'
Stablish some breakpoints in your code and refresh your application, voila!