A UX Designer is responsible for designing and enhancing the user experience (UX) of a website or application. This involves conducting user research to identify user needs and pain points, creating user personas, and developing user flows and wireframes to map out the user journey. The UX Designer also designs and conducts usability tests to gather feedback from users and iterates on designs based on that feedback.

A UI Developer, on the other hand, is responsible for bringing the design to life by writing code that makes the interface functional and responsive. This involves writing HTML, CSS, and JavaScript code to implement the user interface (UI) design. The UI Developer works closely with the UX Designer to ensure that the design is translated accurately into code and that the website or application is optimized for usability and accessibility.

In some cases, the roles of UX Designer and UI Developer may overlap, and a single person may be responsible for both designing the UX and developing the UI. However, in larger organizations, these roles may be separated into distinct positions to allow for more focused expertise and collaboration between the UX and UI teams.