This talk is for developers who want to know how to debug their code in a better way, through single step debugging, profiling, and simpler debugging tools. Xdebug is a PHP extension that implements many debugging aids and features. In this presentation we are going to look at this new version of Xdebug 3. The new version is a near total rewrite, and brings many improvements over its older releases. You will learn how to optimally use the new features and settings to make your development life easier. Besides introducing the redone functionality, we will also have a cursory look at how these features are implemented, just to provide a better understanding of what a debugging extension, can, and cannot do. You will learn: - Which features Xdebug 3 has. - How to debug your application with a single step debugger. - How to make optimal use of the configuration options in Xdebug 3. - How some of the things in Xdebug work.