As is found on Wikipedia “User experience design (UXD, UED or XD) is the process of enhancing user satisfaction by improving the usability, accessibility, and pleasure provided in the interaction between the user and the product. User experience design encompasses traditional human–computer interaction (HCI) design, and extends it by addressing all aspects of a product or service as perceived by users.”
UX designer is the person in charge with creating the products “logic” via wireframes and prototypes via software like Axure, JustInMind, Mockplus etc. Communication is one of the critical skills of the UX designers. They also conduct research, competitive analysis at the beginning as well as usability testing and A/B testing after the project has launched. UX designers are primarily concerned with how the product feels. If your website or app is difficult to use, users will probably be frustrated and move on to something else. If they have a great experience, they’re more likely to come back and tell their friends how great your app is.
Tools of the trade: Sketch, Axure, Mockplus, Fireworks, UXPin