A full-stack developer is a developer or engineer who can build both the front end and the back end of a website. The front end (the parts of a website a user sees and interacts with) and the back end (the behind-the-scenes data storage and processing) require different skill sets.As a full-stack developer, you will work as part of a team to implement new features, as well as make modifications and fix bugs in existing code. Your duties will include designing and developing layouts, writing code to power the underlying functionality of the website, and developing tests for the code you write.A full stack developer works with the front-end and back-end of a website or an application. He or she handles projects anywhere from database design, user interface design, and development. During a project's planning phase, he or she may work directly with clients to understand project deliverables.