Client Server Architechture

The main idea — Clients ask. Servers give. They each have one job.
Client — your phone, laptop, or app. It asks for things — like when you tap a link or open Instagram. It doesn't store anything big. It just shows you what the server sends back.
Server — a big, always-on computer somewhere. It listens for requests, does the work, and sends back the answer. It talks to hundreds of people at the same time.
How it works, step by step:

1. You click a link → your browser asks the server "give me this page"
2. The server gets the request, looks up the data it needs
3. The server sends the page back to you
4. Your browser shows it on screen

Why it's a good system:

• One place for data — everything is saved on the server, not scattered across everyone's devices. Easy to keep safe and up to date.
• Can grow easily — if too many people use it at once, you just add more servers.
• Each side does its own thing — your device handles what you see, the server handles what happens behind the scenes.

User side is everything that runs on your device — your browser or app, the screen you see, and a tiny bit of temporary storage (like saved passwords or cookies). It sends requests and displays whatever the server sends back. It does not make big decisions or store important data.

Server side is everything running on a remote computer — it receives your request, checks who you are (authentication), runs the rules (business logic), talks to the database, and sends back a clean response.