At some point while each of us was growing up, we wished that the adults in our lives would just disappear. They made our lives miserable with their arbitrary rules and restrictions, but they got to do all kinds of fun things. After all, how hard could it be to drive a car, and why did we need them to watch an R-rated movie or to cross the street?
Well, front end developers have a similar fantasy. Their wish is that one day, all back end developers will move out of their way and let them take control. Front end developers are responsible for the things people see and use. All the back end developers need to do is create REST APIs and HTTP endpoints that work and return well-formed JSON, and the front end developers do the rest.