A FreeRTOS developer designs and implements real-time operating systems for embedded devices using the FreeRTOS platform. They write efficient, reliable, and maintainable code, optimize system resources, and ensure the system's responsiveness and stability. They also debug and troubleshoot system issues, often working closely with hardware engineers. Additionally, they are responsible for conducting system tests, validating system functionality, and documenting all their development processes. They may also participate in code reviews and ensure that the system adheres to the set quality standards. They must stay updated with the latest advancements in real-time operating systems and embedded systems.