A Compiler Design developer is responsible for designing, building, and maintaining compilers, crucial tools that translate source code written in a programming language into machine code. They ensure accurate translation of high-level languages into low-level languages, optimize code to enhance execution efficiency, and manage error detection and reporting. They work on different phases of compiler design like lexical analysis, syntax analysis, semantic analysis, optimization, and code generation. Additionally, they may also work on designing interpreters and debuggers. Their work is integral to software development, as it enables the execution of written code on a computer system.