A back end developer is a computer science professional who specializes in functionality that takes place on the server side or backend. As a back end developer, you write code to create software that solves a business need. Your responsibilities are to research the needs of either your employer, or a particular industry, find a problem, and create a software solution. A back end developer differs from a traditional web developer, or front end developer, in that back-end software may not have a user interface or even have exposure to the web.