UX is the experience that your customer has wondering your website. And from here comes designing one into something that makes the customer stay longer and thus create conversions. UI consists in a big part of the UX. It is the “crossover between visual design (look and feel) and the interaction design (how the look and feel work)”, then it creates an interface. It is helping users to roam easily on the website, letting them achieve their goals by knowing what the customer’s needs thus creating the opportunity to achieve it easily.