A full stack web developer is a person who can develop both client and server software. In addition to mastering HTML and CSS, he/she also knows how to: Program a browser (like using JavaScript, jQuery, Angular, or Vue) Program a server (like using PHP, ASP, Python, or Node). Full stack web developers have the ability to design complete web applications and websites. They work on the frontend, backend, database and debugging of web applications or websites.
Work with text editors to use shortcuts and its facilities i.e. Visual studio, Atom, Sublime etc.
Make UI responsible using grid system.
Git and git commands like init, add, commit etc for version control and to work with team.
Other tools like npm & yarn package managers, sass css pre-processor, browser DevTools i.e. chrome devtools.
Understand using HTTP, JSON, GraphQL APIs to fetch data using axios or other tools.
It also requires some design skill to make layout and look better.