User-experience (UX) research and design is a multi-disciplinary field, the objective of which is to shape the entire experience of using a product. Hence, user experience. The user experience is a combination of usability, usefulness, visual communication and design. As a UX designer, you need competence in usability and usability testing, interaction design, information architecture, marketing, business analysis, and applied cognitive psychology. You need to be able to evaluate and know how to measure the quality of visual design, but you do not need to be a graphic designer. User-interface (UI) design is the design of any interface between people and electronic or computer systems. It so happens a lot of that work is done on Web sites and Web and mobile applications, but UI design is not Web design. A competent UI designer applies skills in usability, ergonomics, and accessibility to craft user interfaces that not only look good but meet objective and emotional criteria for good user interfaces, which depend on exactly what kind of interface it is. There’s a massive difference between the interface to a critical-care medical system and a consumer app that orders a taxi. A good UI designer can apply skills and competencies to create the optimal interface to both.