An IIS developer designs, develops, and manages applications for Microsoft's Internet Information Services (IIS) web server platform. This involves creating and configuring websites, handling security aspects, diagnosing and resolving performance issues, and ensuring seamless integration with databases and other services. They use programming languages like ASP.NET and C#. They also troubleshoot issues related to IIS and provide technical support. They perform regular server maintenance, upgrades, and patch management. Moreover, they work closely with other teams such as network administrators and database administrators to ensure optimal server performance and user experience. They also ensure adherence to best practices for web development.