A CMS developer designs, develops, and maintains websites using Content Management Systems (CMS) like WordPress, Joomla, or Drupal. They create customized templates, modules, and features to enhance website functionality and user experience. They perform back-end development, integrating plugins, APIs, and databases to support site functionalities. They ensure the website's responsiveness and compatibility across different browsers and devices. They also manage content, troubleshoot issues, and handle updates and security measures. Additionally, they collaborate with designers and content creators to optimize content according to SEO best practices. Overall, they play a crucial role in creating user-friendly, accessible, and efficient websites.