The term Full Stack Developer is trending nowadays and is being used by many people in the professional world, it has become a new career position.
Basically a Full Stack Web Developer is someone who is capable of developing the front and back-end of a website. He needs to have the knowledge about how to setup and config servers, about server-side API’s, and the client-side scripts and markup/styling language to develop the website’s UI.
The Back-End of a webpage is what makes the Front-End possible. It is where the web server is placed and controlled, it stores all the data in a database, and contains server-side scripts. A Back-End Developer needs to know how to manipulate with web servers, like apache, he also needs to know how to manipulate data in a database and the most common languages/technologies used are PHP, Python, Perl, MysQl, and much more.
So a Full Stack Web Developer needs to know both the Front and Back-End Development.
The salary is obviously bigger for a Full Stack Web Developer than a Front-end or Back-end Developer but it requires a lot more knowledge about how things work.
I think it is great to learn both front and back-end development even if one person is only to develop in one side just because it gives you the expertise to understand the world of web development and if you work on a big company you can interact with your team seamlessly.