An XML Developer is responsible for creating, managing, and optimizing XML-based applications, documents, and data structures. They work with technologies such as XSLT, XPath, XQuery, and XML Schema to structure and transform data efficiently. XML Developers often collaborate with software engineers, database administrators, and business analysts to integrate XML solutions into web services, content management systems, and enterprise applications. Strong knowledge of programming languages like Java, .NET, or Python is often required.