Client-Server Architecture

Overview

The Client-Server architecture is the fundamental model for web applications where clients (browsers, mobile apps) request resources or services, and servers process these requests and send responses back.

This architecture forms the backbone of the internet, enabling distributed computing where responsibilities are separated between the client (user interface and user experience) and the server (business logic, data storage, and processing).

Key Concepts

Client

The requesting entity - typically a web browser, mobile app, or desktop application that initiates communication and presents information to users.

Server

The responding entity that processes requests, executes business logic, accesses databases, and returns responses to clients.

Request-Response Cycle

The fundamental communication pattern where a client sends a request and waits for the server to process it and send back a response.

How It Works

Client initiates a request (e.g., HTTP GET request for a webpage)
Request travels through the network to reach the server
Server receives the request and processes it (may query databases, run business logic)
Server prepares a response with the requested data or confirmation
Response travels back through the network to the client
Client receives and processes the response (renders HTML, displays data)

Use Cases

Web applications (websites, web apps)

Mobile applications communicating with backend services

Email systems (client: email app, server: mail server)

File sharing systems

Online gaming (client: game, server: game server)

Best Practices

Implement proper error handling for network failures

Use HTTPS for secure communication

Implement request timeout mechanisms

Design for stateless interactions when possible

Add caching layers to reduce server load

Implement load balancing for high availability

Interview Tips

What Interviewers Look For

•
Explain the separation of concerns: client handles UI, server handles business logic
•
Discuss how to handle network failures and timeouts
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Mention stateless vs stateful servers and when to use each
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Talk about scaling strategies: vertical (bigger server) vs horizontal (more servers)
•
Explain how load balancers distribute traffic across multiple servers