Backend

The backend is the part you don't see and play with as an end user.

Backends are made of (including but not limited to):

• Servers
• Serverless functions
• CDNs
• Authentication services
• REST APIs
• Databases
• Anything else that isn't that isn't the pretty part of the website that you play with

Did you just log into the website? Sure, you pushed a couple buttons on the frontend but, while you were waiting the backend was hard at work moving a bunch of 1's and 0's around to make sense of the pretty picture that you see on your screen. It was editing data, protecting it in transit, or simply sending you some slice of information so that the frontend could show it to you in a pleasant way.

A metaphor#

When you drive your car, you have a steering wheel, gas pedal, and brake pedal to use. It's nice; they're comfortable to use and sensibly easy to operate.

But what you aren't paying attention to is that the steering column that connects to the front axle to angle your wheels side to side. Or the carburetor that feeds gasoline into your engine block that passes motion to the drivetrain to move your vehicle forward. Or the series of hydraulic systems that made your car stop when you touched the brake pedal.

All that other stuff that you don't touch or worry about? That's the backend.