: Giving invididual feedback to students in large programming courses is time consuming and in most cases not feasible. In order to provide students with feedback we introduce PABS, a tool for automated feedback generation for programming assignments on the Java virtual machine. PABS is a web application giving students the opportunity to submit an arbitrary number of solutions and receive automatically generated feedback. It has been developed to scale with a growing user base by delegating the feedback generation to separate proccesses, called agents, that communicate asynchronously with the web application. At the University of W¨urzburg, PABS is successfully used in many courses that hand out programming assignments.