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Khaled Md Saifullah
Khaled Md Saifullah

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How a Web Server Works - From Beginner to Advanced

#webdev #backend #web

Have you ever wondered what really happens when you type a URL like www.google.com into your browser and hit Enter?

Behind the scenes, a web server plays the central role in delivering that website to your screen.

In this blog, I will cover how a web server works starting from the beginner friendly basics and moving towards concepts that even advanced developers should know.

Whether you are just starting with web development or are a seasoned backend engineer, this blog will help you understand the core engine of the web.

What is a Web Server?

A web server is a software (sometimes hardware) that:

  • Stores, processes and delivers web content (HTML, CSS, JS, images, APIs)
  • Uses the HTTP/HTTPS protocol to communicate with browsers (clients)
  • Runs continuously to serve multiple requests from users worldwide

Popular Web Servers:

  • Apache (Open-source, widely used)
  • Nginx (Lightweight, fast, handles concurrent requests)
  • Microsoft IIS
  • LiteSpeed

How a Web Server Works - Step by Step

1. User Request (Client Side)

  • You type https://example.com in your browser
  • The browser sends an HTTP request to the server hosting that domain

2. DNS Resolution

  • The domain (example.com) is mapped to an IP address via the Domain Name System (DNS)
  • Example: example.com → 192.168.1.1

3. TCP/IP Connection

  • The browser establishes a connection using TCP/IP with the server’s IP
  • If it is HTTPS, an SSL/TLS handshake happens for encryption

4. Server Processing

  • The web server receives the request
  • It checks if it’s a static file (HTML, CSS, image) or requires dynamic content (PHP, Node.js, Python etc.)
  • For dynamic content, the server passes the request to an application server (e.g. Express.js, Django, Laravel)

5. Database Query (if needed)

  • If the request involves user data, product lists, or authentication, the server fetches data from a database (MySQL, MongoDB, PostgreSQL)

6. Response Sent Back

  • The server sends back an HTTP response with:
    • Status Code (200 OK, 404 Not Found, 500 Server Error)
    • The requested data (HTML page, JSON response etc.)

7. Browser Renders Content

  • The browser receives the response
  • Parses the HTML, loads CSS/JS, and finally renders the webpage for the user

Beginner to Advanced Concepts

Beginner Concepts

  • HTTP vs HTTPS → Secure data transfer
  • Static vs Dynamic Websites → Prebuilt files vs generated on the fly
  • Client-Server Model → Browser (client) vs Server (backend)

Intermediate Concepts

  • Load Balancing → Distributing requests across multiple servers.
  • Caching → Storing data temporarily for faster responses (CDN, browser cache)
  • Session Management → Handling user login, cookies, tokens

Advanced Concepts

  • Reverse Proxy → Nginx/HAProxy handling traffic before backend servers
  • API Gateways → Managing microservices and requests
  • Scalability → Horizontal scaling (adding more servers) & vertical scaling (upgrading server resources)
  • Security → DDoS protection, WAF (Web Application Firewall), SSL/TLS encryption

Example Workflow Diagram 

[ Browser ] --> [ DNS Lookup ] --> [ Web Server ] --> [ App Server ] --> [ Database ]
      ^                                                           |
      |---------------------- Response Back ----------------------|
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Why Developers Should Understand Web Servers

  • Helps debug performance bottlenecks
  • Essential for deploying apps on platforms like AWS, Vercel or DigitalOcean
  • Enables writing scalable, secure applications
  • Builds knowledge of networking, security and system design

Key Takeaways

  • A web server is the backbone of the internet, delivering content to users
  • From typing a URL to seeing a webpage, multiple layers like DNS, TCP/IP, SSL, and HTTP are involved
  • Beginners should focus on client-server basics, while advanced developers should explore load balancing, caching, and security

Conclusion

Understanding how a web server works is non-negotiable for every developer. Whether you are building a personal portfolio site or a large scale SaaS platform, knowing the internals of servers will help you build faster, safer= and more scalable web applications.

Thanks for reading!

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