The objective of this lecture is to give pentesters and tool developers an overview of the APIs available to extend the Burp Suite intercepting proxy. Using open-source examples developed by the author we will illustrate a number of key areas for anyone wishing to create extensions for Burp Suite: - Passive scanning - Active scanning - Identifying insertion points - Request modification The presentation will include code samples and links to actual open source Burp Suite plugins developed by the author.