Every app has five layers.

This is everything your users see and touch. The buttons, the pages, the animations. If your app were a restaurant, this is the dining room — the tables, the menu, the lighting.

When someone taps a button, something has to figure out what happens next. That’s the backend. It receives requests, makes decisions, and sends answers back. It’s the kitchen — you never see it, but nothing works without it.

Your app needs to remember things — who signed up, what they saved, what they bought. The database is a giant organized notebook that never loses a page. Every account, every message, every transaction lives here.

How does your app know who’s who? Authentication checks IDs at the door. It handles logging in, logging out, and making sure people can only see what they’re allowed to see.

You’ve built the restaurant, hired the kitchen, trained the staff. Now you need an address so people can find you. Hosting puts your app on the internet with a real URL that loads fast anywhere in the world.