When you enter a web page or an application, it immediately sends you to the start where you get the menu with all the features, including the site map, all this is inside the Frontend, the part of the application or website that is displayed to the user.
A Front-end developer in Rootstack is in charge of the design and implementation of the interface of the web page or mobile application. His responsibility is to make sure that the design created by the web designer works correctly online, for this he uses programming languages such as CSS, HTML, and JavaScript.