Is IIS a Web Server or an Application Server?


Larry Thompson

When it comes to hosting websites and applications, there are two terms that often come up: web server and application server. These terms can sometimes be confusing, especially when it comes to Microsoft’s Internet Information Services (IIS).

So, is IIS a web server or an application server Let’s dive into the details.

Understanding Web Servers

A web server is responsible for handling HTTP requests from clients (usually web browsers) and sending back the requested HTML pages or other resources. It primarily serves static content, such as HTML, CSS, JavaScript files, images, and videos. Web servers are designed to efficiently handle numerous concurrent connections and deliver content quickly.

IIS as a Web Server

IIS is indeed a powerful web server developed by Microsoft. It has been the default web server for Windows operating systems since Windows NT 4.0. IIS supports various protocols like HTTP, HTTPS, FTP, SMTP, etc., making it versatile for different types of web applications.

But what makes IIS more than just a regular web server

Going Beyond with IIS

IIS not only serves static content but also supports dynamic content through various modules and extensions. This ability allows it to handle complex web applications beyond simple static websites.

IIS as an Application Server

An application server, on the other hand, provides an environment for running dynamic applications by executing code in response to client requests. It typically supports multiple programming languages and frameworks like ASP.NET or PHP.

In the case of IIS, it can act as both a web server and an application server simultaneously. By leveraging modules like ASP.NET or PHP extensions, IIS can process dynamic content and execute server-side code to generate HTML on the fly.

So, to answer the question:

  • IIS is a web server because it handles HTTP requests and serves static content.
  • IIS is also an application server because it can execute server-side code and handle dynamic content.


IIS is a versatile tool that can serve as both a web server and an application server. Whether you need to host static websites or complex web applications, IIS provides a robust platform with its extensive features and support for various programming languages. So, next time someone asks you if IIS is a web server or an application server, confidently tell them it’s both!

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