A front-end engineer, also known as a front-end web developer, develops, tests, and maintains the user interface of a website. The front-end developer focuses on the look and feel of the site, along with its functionality. He or she works closely with a designer for how the site should look and with a backend engineer for how the site should feel. His main focus is the presentation layer and not necessarily the logic layer. Note that for mobile the title of mobile engineer is often used.