A Functional Requirements developer is responsible for defining, analyzing, and documenting the essential functionalities needed in a software system. They translate business needs into technical descriptions to guide software development. Their role includes conducting stakeholder meetings to gather requirements, creating detailed functional specifications, validating the developed features against the requirements, and facilitating communication between the business and technical teams. They also collaborate with other developers and testers to ensure the software meets the outlined requirements. Their work forms the basis for system design and development, ensuring the final product serves its intended purpose efficiently.