# Debugging PHP

## Table of Contents

- Using the Debugger
- Debugger Protocol

## About the debugger

PHP 3 includes support for a network-based debugger.

PHP 4 does not have an internal debugging facility. You can use one of the external debuggers though. The » Zend IDE includes a debugger, and there are also some free debugger extensions like DBG at » http://dd.cron.ru/dbg/, the » Advanced PHP Debugger (APD) or » Xdebug which even has a compatible debugger interface as PHP 3's debugging functionality as is described in this section.