An IIS . developer is responsible for creating, managing, and optimizing web applications on Microsoft's Internet Information Services . platform. This includes designing and implementing application architecture, ensuring security and scalability, troubleshooting issues, and optimizing performance. They also handle application migration and configuration, and work on server-side scripting. They work closely with other team members, such as database administrators and front-end developers, to ensure seamless user experience. Familiarity with .NET, ASP.NET, and other Microsoft technologies is crucial for this role. They also need to keep up-to-date with the latest industry trends and advancements.