Photo By: Tim van der Kuip
Back-End developers are responsible for everything else that the front-end developers are not. I know, I know, that is one incredibly helpful definition. So going back to our home analogy, back-end developers are responsible for the electrical wiring, plumbing, air ducts, insulation, etc. They mainly take care of and handle all of the stuff that the user never sees; it goes on "behind the scenes." A front-end developer puts the light switch on the wall, and the back-end developer makes sure the light turns on when you flip the switch.
You need both to make a home.
Full-Stack developers are capable of doing both front-end and back-end. In theory, they are capable of doing the jobs of two separate people all by themselves. However, in practice, this theory is flawed significantly, in my opinion. Truth is a lot of web developers can do both front-end and back-end jobs, but they are always stronger in one of them. It is never equally divided. They always lean to one side.
You don't need to make up your mind about which side you are going to choose, as this site exposes you to both. You are going to learn front-end and back-end skills, the "full-stack." Once you get a little more knowledge and experience under your belt, you will be better able to determine which side you prefer and like more.