An ABAP Web Dynpro developer designs, builds, and maintains applications using ABAP Web Dynpro, a programming model for SAP's web-based applications. They create user interfaces, write code to manage application logic, and integrate with backend systems. They also handle debugging, testing, and troubleshooting to ensure optimal functionality. Their role involves improving the application's performance and usability, adhering to coding standards and best practices. They also collaborate with other team members to define requirements, design solutions, and solve complex problems. Additionally, they may provide user support and training, and document the application's design and functionality.