A Constraint Programming developer works on designing, implementing, and optimizing algorithms for solving complex computational problems. They use constraint programming languages to define variables, domains, and constraints, which are then solved by automated solvers. Their work is crucial in areas like scheduling, routing, and planning where solutions must satisfy a set of constraints. The developer needs to understand the problem, break it down into smaller parts, model it appropriately, and translate it into a constraint programming language. They also analyze results, troubleshoot issues, and refine models to improve performance. Their goal is to find the most efficient solution within defined parameters.