Chapter 6: Web Servers — Nginx and Apache

6.1 What is a web server?

By Ravindra Bagale · Last updated: 25 September 2026

Mitranno, till now we launched a server. But a server without a web server is like a shop with the shutter down — customers come but nobody serves them. Let's understand what a web server really does. A web server is software that listens on a port (80 for HTTP, 443 for HTTPS), accepts HTTP requests from browsers and returns responses — HTML pages, images, CSS, JavaScript files, or data produced by an application.

  Browser                         EC2 instance
 +--------+   GET /index.html    +---------------------------------------+
 |        | -------------------> | Web server (Nginx / Apache) :80       |
 |        |                      |   ├─ static file?  → read from disk   |
 |        | <------------------- |   └─ dynamic?      → pass to PHP /    |
 +--------+   200 OK + HTML      |                      Node / Python app|
                                 +---------------------------------------+

A web server does three main jobs:

1. Serve static content — files that are the same for everyone (HTML, CSS, JS, images).
2. Pass dynamic requests to an application (PHP-FPM, Node.js, Gunicorn) — called reverse proxying — and return its output.
3. Handle cross-cutting concerns — TLS/HTTPS, compression, caching, logging, virtual hosts (many websites on one server), load balancing, rate limiting.

Common HTTP status codes