A Full Web Stack Developer is a professional who handles all aspects of web development including front-end, back-end, database, version control, server, API, and deployment. They design user interactions on websites, develop servers and databases for website functionality, and code for mobile platforms. They create the public face of a website and manage the infrastructure behind it. They are skilled in languages like HTML, CSS, JavaScript, and use development frameworks and third-party libraries. They also manage hosting environments, perform testing, and handle security and data protection. Essentially, they can single-handedly plan, manage, and build software applications.