Just write your business logic in a function, they do the rest. Who has time to build a boring backend these days? First of all it’s boring, you already know how your app looks like and what data you want to display on your screen, but still, you need to install a server, configure your environment, blablabla, hire backend folks, hire more expensive backend leads to scale. At the end of the day all you need is something that returns a simple response in a string format (for example). It is scale-as-a-service / build-a-better-user-experience. That’s the main concept of Serverless.