A Delphi developer designs, codes, tests, and debugs software applications using the Delphi programming language. They work with clients or end-users to define system requirements and develop software to meet those needs. Their responsibilities include modifying existing software to correct errors or improve performance, analyzing user needs and software requirements, and coordinating software system installation. They also document every aspect of an application as a reference for future maintenance and upgrades. Delphi developers may work in various industries, ranging from technology companies to government agencies, and they often collaborate with other developers and IT professionals.