A developer primarily designs, develops, and improves web-based applications using various programming languages such as HTML, CSS, JavaScript, and PHP. They are responsible for creating user-friendly interfaces, optimizing web functionality, and ensuring website compatibility across different browsers and devices. They work closely with other team members to integrate backend functionalities. Additionally, they troubleshoot and fix bugs, maintain code quality, and stay updated with the latest web development trends. They also assist in database design and management, ensuring data security and integrity. Communication skills are crucial as they often explain complex technical concepts to non-technical stakeholders.