How web apps work
What happens when you open an app
Before you build real apps with AI, it helps to know what the parts of an app are called. No jargon, promise. You only need a simple picture in your head.
A web app is like a restaurant
Think about eating at a restaurant. You sit in the dining room, order from a waiter, and food arrives from a kitchen you never see. A web app works the same way.
- Dining room = frontend. The part you see and click: buttons, pages, pictures.
- Waiter = API. Carries your order to the kitchen and brings the food back.
- Kitchen = backend. Does the real work out of sight, like checking a password or asking an AI model.
- Pantry = database. Stores everything the kitchen needs: products, users, orders.
For example, when you search "plant pots" in an online shop, the page sends your search to the backend. The backend looks in the database and sends back the matching products.
What you'll learn
How to use this section
You won't write any code here. The goal is to understand the words your AI tools will use. Every page follows the same format:
- What is it? — A simple analogy and explanation
- See it in action — Real examples and prompts you can copy
- Try it yourself — Short practice questions
- Common mistakes — Things to watch out for
Practice
Try these exercises to lock in what you just learned.
What's next?
Let's start with the two halves of every app: the frontend you see and the backend you don't.