Computer science · the big picture
How the web really works — under the hood
Every app you love — games, YouTube, even Astra — is built from a handful of simple parts working together. Here they are, explained with a restaurant you already understand. 🍽️
Frontend
The dining room & the menu
The part you see and tap — the buttons, colours and pictures on the screen.
🛠 HTML, CSS & JavaScript
Backend
The kitchen
The hidden brain that does the real work — cooking up exactly what you asked for.
🛠 Python & other languages, on a server
Database
The recipe book & the fridge
The app's memory — where every fact is stored and found again in a flash.
🛠 Postgres — that's what Astra uses!
Client & Server
You order, the kitchen delivers
Your phone is the client — it asks. A big computer far away is the server — it answers, in a blink.
🛠 The internet carries the message
Operating System
The restaurant manager
The boss of every device — it runs the apps and shares the screen, memory and files fairly.
🛠 Windows, macOS, Android, Linux
More building blocks of computer science
The other big ideas that make computers and the web work.
Algorithms
A step-by-step plan to get something done — like a recipe, or the steps to get dressed.
Code
How we write those steps in a language the computer understands — like Python!
Bugs & debugging
When code goes wrong, you turn detective and hunt down the mistake.
The Internet
The roads that carry messages between every computer in the world.
Security
Passwords and secret codes (encryption) that keep your information safe.
The Cloud
Powerful computers, always on, that companies rent — where apps like Astra live.
Hardware
The physical parts: the CPU (brain), memory (desk) and storage (drawers).
AI
Teaching computers to spot patterns and make guesses — explore it in the AI Frontier.
What happens when you open a website?
All of this happens in under a second.
You type the address
…like placing your order.
It zips to the server
the order reaches the kitchen.
The backend asks the database
the chef fetches the ingredients.
The page comes back
your meal arrives, beautifully plated — your browser draws it.
You're inside one right now! 🚀
Astra's frontend is what you see; its backend runs your Python; its databaseremembers your progress. You're not just learning aboutthe web — you're standing inside one.