What is Nginx?

Nginx (pronounced “engine-x”) is a high-performance web server and reverse proxy server.

It is mainly used to serve websites, forward requests to backend servers, and handle lots of web traffic efficiently.

What Nginx can do (core functions)

Function What it means
Web server Serve static files (HTML, CSS, JS, images) to browsers
Reverse proxy Receive client requests and forward them to backend servers (like Node.js, Java, Python apps)
Load balancer Distribute incoming traffic across multiple backend servers to balance load
SSL termination Handle HTTPS (encryption) and forward unencrypted traffic to backend
Caching Cache content to speed up responses and reduce backend load
HTTP/2 support Serve modern web traffic more efficiently

✅ Fast & lightweight — Handles thousands of concurrent connections with low memory ✅ Open source & free ✅ Easy to configure (small config files) ✅ Extremely reliable — Runs on millions of websites (e.g., Netflix, Dropbox, WordPress)

Example of Nginx reverse proxy (config)

server {
    listen 80;
    server_name example.com;

    location / {
        proxy_pass http://localhost:3000;  # Forward requests to backend app
    }
}

This simple config says: “Listen on port 80 → forward all traffic to a backend server running on port 3000.”

In short

Nginx is a web server + reverse proxy + load balancer that is fast, reliable, and free. It helps route, serve, and optimize web traffic between clients and backend servers.