A Mochiweb developer designs and builds web applications using the Mochiweb library in Erlang programming language. Their work involves creating high-performance, scalable HTTP servers and handling low-level HTTP protocols. They manage request processing, handle client connections, and use Erlang's concurrent processing capabilities for efficient real-time data handling. They also debug and optimize the performance of the web services. As Mochiweb supports REST principles, developers often create RESTful APIs for communication between different software components. They also ensure system robustness and reliability, considering Erlang’s fault-tolerance characteristics. They may collaborate with other developers, maintaining the codebase and integrating new features or updates.