Web designers plan, create and code web pages, using both non-technical and technical skills to produce websites that fit the customer's requirements. They are involved in the technical and graphical aspects of pages, producing not just the look of the website but determining how it works as well. Web designers might also be responsible for the maintenance of an existing site. The term web developer is sometimes used interchangeably with web designer, but this can be confusing. Web developing is a more specialist role, focusing on the back-end development of a website and will incorporate, among other things, the creation of highly complex search functions.