A developer is primarily responsible for designing, coding, and modifying software applications. They analyze user needs and develop software solutions with the aim of optimizing operational efficiency. They are tasked with the creation of high-quality, innovative, and fully performing software that complies with coding standards and technical design. They also debug and fix issues, perform software updates, and ensure the functionality and efficiency of systems. Additionally, developers collaborate with other team members, including system architects and analysts, to assess system performance and make necessary improvements. They use their understanding of various programming languages to ensure software reliability.