This project will benefit students in 15-122 Principals of Imperative Computation at Carnegie Mellon University by helping them create correct programs. The C0 Debugger will enable students to understand how their programs execute and find where problems originate more easily than with existing tools. In addition to debugging, students will have better knowledge for how the underlying computation model works when evaluating their code. The C0 Debugger will also enable students to test simple programs with little setup, using only a web browser. They will no longer have to set up and become familiar with a Unix environment before they can program, making C0 accessible to more people.