Understanding Webservers: How They Work in the World of Tech

Published on January 15, 2026

Understanding Webservers: How They Work in the World of Tech

In the digital world, we often hear the term “web server” thrown around, but what exactly is a web server? At its core, a web server is a computer system that processes requests from clients (such as web browsers) and delivers content via HTTP/HTTPS over the internet. This process involves a complex interaction of protocols, hardware, and software properly configured to make a web application or website available to the end user. In this article, I will focus on web server software and what it does. For the purposes of explanation, when I say “web server”, in this article I mean the software that is interacting with a web client and I do not mean the virtual machine or hardware that the web server is running on.

What is a Web Server?

A web server is a combination of hardware and software that stores, processes, and delivers web content—such as HTML pages, images, videos, and applications—to users over the internet. It listens for requests from clients, typically web browsers, and responds with the requested content, usually in the form of HTML, CSS, JavaScript, or other media files. The web server operates on a client-server model, where the client (browser) sends a request, and the server responds with the appropriate data.

Types of Web Servers

Here are several types of web servers in no particular order, each with its own strengths and use cases:

1. Apache HTTP Server - One of the most widely used open-source web servers, known for its flexibility, extensive module support, and compatibility across platforms like Windows, Linux, and macOS
2. Nginx - A high-performance web server and reverse proxy known for handling high traffic with low resource usage, strong support for load balancing, and popular in modern web architectures.
3. Microsoft IIS - A proprietary web server developed by Microsoft, tightly integrated with Windows Server and commonly used in Windows-based enterprise environments.
4. Lighttpd - A lightweight, fast web server designed for high concurrency and low memory consumption, suitable for embedded systems and small to medium websites.
5. Apache Tomcat - A Java-based server for running Java servlets and JSP (JavaServer Pages), widely used for enterprise Java applications.
6. Caddy - An open-source web server with automatic HTTPS configuration (via Let’s Encrypt), simple configuration, and strong support for modern web standards.

How Web Servers Function

Web servers function through a series of well-defined steps that involve request handling, processing, and response delivery, each with specific technical mechanisms:

1. Receiving Requests: The web server listens on specific ports (usually port 80 for HTTP and port 443 for HTTPS) for incoming TCP connections from clients:

   • The server typically employs a multi-threaded or event-driven architecture to handle concurrent connections efficiently
   • When a TCP connection is established, the server begins to receive the HTTP request data, which consists of a request line, headers, and optionally a message body.

2. Processing Requests: When a request is received, the server parses the HTTP request using a parser that validates the syntax and extracts key components:

   • The request line contains the HTTP method (GET, POST, PUT, DELETE), the requested URI, and the HTTP version
   • HTTP headers are parsed for additional information such as Content-Type, Accept, User-Agent, and Authorization
   • The server performs request validation including checking for malformed requests, invalid headers, and security-related checks
   • URL decoding is performed for special characters in the requested path
   • Query parameters are parsed and made available to application logic

3. Locating Resources: The server searches for the requested resource through a structured process:

   • URI mapping: The server translates the requested URI to a file system path or application endpoint
   • Virtual host handling: For servers hosting multiple domains, the server determines which site configuration to use based on the Host header
   • Directory indexing: If a directory is requested without an explicit index file, the server looks for configured index files (index.html, index.php, etc.)
   • Dynamic resource handling: For scripts or applications, the server may invoke a CGI process, FastCGI handler, or application server to generate content
   • Static file serving: For simple files, the server reads directly from the file system

4. Generating Responses: Once the resource is located, the server prepares a structured HTTP response that includes:

   • Status line with HTTP status code (200 for success, 404 for not found, 301 for redirect, etc.)
   • HTTP headers providing metadata such as Content-Type, Content-Length, Cache-Control, and Set-Cookie
   • Response body containing the actual content, which may be static or dynamically generated
   • Proper error handling for cases like 404 Not Found, 403 Forbidden, or 500 Internal Server Error
   • Content negotiation based on Accept headers and client preferences

5. Sending Responses: The server sends the response back to the client through the established TCP connection, with considerations for:

   • Connection management (keep-alive vs. close connections)
   • Chunked transfer encoding for large responses
   • Compression (gzip, deflate) for content optimization
   • Proper buffering and streaming of content
   • Timing and performance considerations for response delivery
   • Security headers and CORS policies when applicable
   • Response caching mechanisms to improve performance

Web Server Uses

Modern web servers are often part of a larger architecture that includes:

• Hosting Websites: They provide the software for websites to be accessible on the internet. The original use case for web servers which served HTML documents to web clients.
• Load Balancers: Distribute traffic across multiple servers to ensure optimal performance and availability. Here a load balancing web server allows us to direct traffic to multiple instances of our same application in order run a proper fault tolerant and redundant workload.
• Reverse Proxies: Act as intermediaries between clients and servers, handling requests on behalf of the backend servers. This is useful when you want the web server itself to terminate TLS and not the application that is being proxied to.
• Caching Systems: Store frequently accessed content to reduce load and improve response times. Think Cloudflare, Netlify, or Vercel content delivery networks (CDNs).
• Application Servers: Handle dynamic content generation and business logic. Here you can imagine REST APIs that handle more complex requests than just serving html to a web browser.

Key Technologies and Protocols

Web servers operate using several key technologies and protocols:

• HTTP/HTTPS: The primary protocol for communication between clients and servers.
• TCP/IP: The foundational protocol suite for internet communication.
• SSL/TLS: Security protocols that encrypt data transmitted between clients and servers.
• CGI/FCGI: Technologies that allow servers to execute scripts and generate dynamic content.

Choosing the Right Web Server

Selecting the right web server depends on several factors. While Nginx is my go-to web server, I recognize that the others are quite competent and widely used. Here are possible criteria that you might use to determine which web server you want to use.

• Performance Requirements: Web servers have differing approaches to performance, but generally webservers are lightweight and quite fast because they are designed to serve large numbers of concurrent requests quickly.
• Security Needs: Most well-known and widely used web servers keep abreast of known security vulnerabilities and patch them accordingly.
• Integration Needs: Your web server choice may depend on what you are already using in other places in order to keep the tech stack small. If this is the first time you’re using a web server, you probably can’t make a wrong decision. If one stands out to you more than another because of ease of use and simple integration, then pick that one and keep building.
• Scalability: Scaling is important, but as stated in the performance section, most web servers are built with the intent to serve thousands or tens-of-thousands of users and therefore, have typically designed the web server to scale correctly.

Conclusion

I have had to deploy a number of web servers in my career as a DevOps engineer. Knowing what they can be used for and are capable of gives rise to many networking troubleshooting conundrums. For example, knowing that Nginx can operate as a layer 4 proxy with its stream module so you can stream an incoming request through to an always on VPN connection in order to properly traverse Carrier Grade NAT, opens a world of possibilities for hosting applications on your own home infrastructure. Get out there and use one in your current setup and start building your own web network.