The uX designer's main task is to improve the user use on any platform. It focuses only on the expectations and needs of the user, taking into account the project objectives of his client. Its role is crucial: it must simplify the use that users make and create a positive emotion by incorporating a "story telling" to the user experience in order to retain them. Its role is to facilitate the handling of the site, its accessibility and generate confidence among users. In contrast, UX designers who are interested in the user experience, UI focused on the visual look and feel of the product. They are responsible for every page designer with which the user interacts and ensures consistency with the visual "road user" directed by the UX Designer. It will look for example to visually define the error displays on the pages.