A G-code developer creates and modifies programs used in Computer Numerical Control (CNC) machinery, which fabricates parts and tools for various industries. They utilize G-code, a unique language that directs CNC machines on how to perform tasks. Their responsibilities include interpreting blueprints and technical drawings, determining the sequence of machine operations, and writing the necessary G-code. They also perform testing and debugging to ensure the G-code programs run correctly. Their work is crucial in manufacturing processes, as it helps in automating production and ensuring precision in the creation of parts and tools.