A JEE (Java Enterprise Edition) developer designs, develops, and manages applications using the Java Enterprise Edition platform. They work on various components like web services, enterprise beans, and servlets, as per client or project requirements. They ensure applications are secure, scalable and maintainable. Developers may also be involved in the integration of databases and servers, debugging, and testing applications to ensure optimal performance. They may also collaborate with other developers and stakeholders, and often provide technical support for developed applications. Their work is often used in large-scale, distributed, transactional and highly available applications that are crucial for businesses.