Extending OpenPTK, the User Provisioning Toolkit by Masoud Kalali -- Project Open Provisioning ToolKit (OpenPTK) is as an open source user provisioning toolkit exposing APIs, web services, HTML taglibs, and JSR-168 portlets with user self-service and administration examples. OpenPTK hides the implementation differences between different user stores, allowing developers to use multiple stores with a common API. Masoud Kalali shows how to use and extend the toolkit.