An online tool that helps students and instructors to teach and learn basic concepts in automata theory. Provides automated feedback to the student if they provide a wrong automaton. You can try it out here.
During my work on my Master's thesis I have contributed to AProVE, a powerful tool for proving termination of Java-, C- and Prolog-Programs.
When I was a research assistant at the Group for High Performance Computing of the IT Center of RWTH Aachen University, Christian Iwainsky and I started development on InstRO, a tool for instrumentation of C- and C++-code.