How important are back-end developers? Well, they’re key to most tech projects getting off the ground. Quite simply, these software engineers build the programming skeleton and — if we stick with the personification — the muscles too. A front-end developer may layer on the skin and decide on the color of the eyes, but it’s the back-end developer who enables the project to stand up and do what needs to be done.

Back-end developers play a critical role in any development team, one requiring training and specific skills. Here’s what you need to know if you want to become one, too.

What is the back end, anyway?

An application’s back end is something the user never sees, but it does the actual work of the application. That includes establishing the structure of the software, the API, the logic and retrieving and storing data.

Let’s say you’re creating loyalty-program software for an airline. The parts that the average user views — the menus, flashy graphics, maps and promotional copy — are all elements of the front end of the programming. The back end is what happens once the user presses a menu button. When she enters her user ID, the back end checks her loyalty program number against the one on file on the airline’s server and gives her access to the account. If she wants to check how many airline miles she has, the back end retrieves that number from the airline’s secure database. And if she decides she wants to cash in her miles for a trip, the back end communicates with the airline’s reservations system; offers her a list of available routes, scheduled flights and seats; then books the flight she wants and deducts the spent airline miles from her balance.

In other words, the back end has to be able to communicate seamlessly not only with the front end of the application but also perform security functions, access the airline servers, read from and write into databases, deduce what flights the user might want, and calculate airfare, taxes, service fees and so on. In short, it’s the back-end developer’s job to make sure that the application actually functions. 

What skills does a back-end developer need?

A back-end developer needs to know not only how to create the code that will coordinate everything an application will do, but what to do to keep that application running and how to fix it if a problem arises. They’ll also need to make sure it interacts seamlessly with the front end, handle data applications and more.