What is web server? Explained: Definition, Advantages, and More

By Bhargab
8 Min Read

Here is an explanation of “What is web server?“, its definition, advantages, and more:

A web server is a computer software and underlying hardware that accepts requests via HTTP (Hypertext Transfer Protocol) or HTTPS (HTTP Secure) protocols from client machines – usually web browsers – and serves them appropriate web pages or other content.

Definition: What is web server?

A web server consists of a physical server machine, server operating system like Windows or Linux, web server software like Apache or Nginx, website files, databases and backend programming/scripts. All these respond to client requests for websites, apps, assets and data from anywhere in the world via the internet.


How Does a Web Server Work?

What is web server?

A web server is a critical piece of infrastructure that delivers web pages and applications to users over the internet. When you type a website URL into your browser, a web server is working behind the scenes to accept your request, fetch the required content, and serve the response.

But how does this all actually happen? Here is a high-level overview:

  1. Browser Sends a Request

It starts with your browser creating an HTTP request when you enter a URL. This request includes:

  • The HTTP method (GET, POST, etc.) indicating the operation being requested
  • The path and file name of the resource being requested
  • Headers with information like browser type, formats supported, cookies, etc.

This request gets sent to the target server identified by the domain name in the URL.

  1. Web Server Accepts Request

The web server is continuously listening for incoming requests made to the host machine’s IP address using HTTP over port 80. When an HTTP request comes in, the web server software (like Apache or Nginx) accepts it and processes the headers to determine what exactly is being asked for.

  1. Server Generates a Response

Next, the web server handles what’s needed to formulate an appropriate response. This may involve:

  • Fetching static HTML, CSS, JavaScript, image or other files from disk and returning their contents to the browser
  • Processing server-side languages like PHP that generate HTML dynamically
  • Accessing internal APIs or external web services as part of a server-side application logic
  • Querying databases to return requested data
  1. Server Returns Response

Once the required processing is complete, the web server assembles a response in the format laid out by the HTTP protocol. This includes status codes indicating success, redirect or errors along with requested files, dynamic content and headers in the response body.

This response gets sent back to the browser that made the initial request so it can handle displaying or processing the returned content.

Of course many additional complexities exist, but at a basic level this request-response sequence underlies all web browsing and dynamic website functionality that enriches the modern internet experience.

Advantages of using a web server

  • Centralized content and ability to update it easily from one place rather than each user computer.
  • Shared hosting and economies of scale. Multiple sites and apps can reside cost-effectively on the same server.
  • Better security and backups possible with dedicated hosting space and tools.
  • High availability through redundant web servers, data centers etc.
  • Scalability to handle growing traffic through server capacity and horizontal scaling out.
  • Supports interactive pages and user input processing without needing software installation on user devices.
  • Accessibility from anywhere just using a web browser, no hardware constraints

Examples of Web Servers

Here are some of the most popular web servers and examples of their use:


The Apache HTTP Server, colloquially called Apache, is the most widely-used web server software. Some key facts about Apache:

  • Open-source software maintained by the Apache Software Foundation
  • Runs on both Unix-based operating systems like Linux and BSD as well as on Windows
  • Known for being reliable, efficient and secure
  • Powers around 37% of all active websites, like Facebook and Wikipedia


Nginx (pronounced “engine-x”) is another leading open-source web server:

  • Has a lightweight memory footprint compared to competitors
  • Implements advanced load balancing and reverse proxy functionality
  • Can accelerate content and application delivery using features like HTTP caching
  • Used by around 30% of websites, including Netflix, Hulu and GitHub

Microsoft IIS

Microsoft’s Internet Information Services (IIS) dominates the market share for Windows-based web hosting:

  • Tightly integrated with other Microsoft server products
  • Supports ASP.NET, a popular web app development framework from Microsoft
  • Includes server management tools and GUIs available in Windows Server operating systems
  • Used by over 13% of all websites, with many Microsoft-centric sites

There are of course many more great options like Caddy, Tomcat, lighttpd and others that serve niche use cases as well. But Apache, Nginx and IIS handle a majority of sites that compose the modern web. Understanding these leading platforms helps when administering servers online today.

Web server security practices

Here are some best practices for securing web servers:

Keep Software Updated

Apply the latest security patches and updates for the web server software, operating system, languages, and applications. Sign up for notifications about new releases that resolve vulnerabilities to upgrade promptly.

Harden Configuration

Disable unnecessary services & features, remove default sample applications, enable domain name restrictions, and follow other hardening guidelines specific to the web server software.

Enable HTTPS

Require HTTPS connections by generating an SSL/TLS certificate and redirecting HTTP traffic. This encrypts sessions and prevents sensitive data from being transmitted insecurely.

Implement Access Controls

Leverage firewall policies, OS-level permissions, .htaccess rules, and web server features to limit connections and access to approved sources only. Authenticate users and restrict access to authorized personnel.

Sanitize Input Data

Scrub user input from forms, URLs and request parameters to prevent cross-site scripting, SQL injection or other attacks that may leverage malicious data.

Store Data Securely

If the web server connects to a database or data store, ensure strong credentials are used while connections are encrypted. Follow least privilege and best practices in granting data access.

Monitor Activity

Review access logs and set up alerts to detect anomalies indicating potential attacks or unauthorized access attempts in real time.

Create Backups

Automatically back up both web server configuration and any website or application data regularly to enable recovery from malware or data loss.

Following security best practices requires ongoing vigilance, but taking these critical steps makes the web server much harder to compromise.

Summary: What is web server?

In summary, a web server makes it possible to securely host, manage and deliver content in websites and web applications reliably to users across the world with good performance. This makes web servers a critical backbone infrastructure element of the internet we use extensively today.

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