Internet Information Server is Microsoft's web server software that runs websites on Windows computers

Internet Information Server (IIS) is the software that takes requests from browsers, finds the right files on a Windows computer, and sends them back. It does the same job as Apache or Nginx on Linux servers, but it's built by Microsoft and runs only on Windows. If your hosting provider uses Windows servers instead of Linux, IIS is almost certainly what's running your site.

You don't interact with IIS directly — your hosting provider installs and manages it. But understanding what it is helps you know why your hosting plan specifies "Windows hosting" or "IIS hosting", and what that choice means for your website's tools and costs.

Key Takeaways

  • IIS is Microsoft's web server software that runs on Windows and does the same job as Apache or Nginx on Linux — it receives browser requests and sends back website files.
  • Windows hosting with IIS costs more than Linux hosting because Windows licenses are expensive, so you pay that difference in your monthly bill.
  • IIS is the only choice if your site uses ASP.NET, Microsoft SQL Server, or other Microsoft-specific tools, but most websites work fine on cheaper Linux servers.
  • Your hosting provider manages IIS completely — you don't install or configure it yourself, but you may see "IIS" in your hosting plan name or documentation.
  • IIS and Apache can both run the same basic websites, but they handle some tasks differently and have different security settings to learn.

How IIS receives and answers browser requests

When someone types your domain into a browser, that browser sends a request to your hosting provider's server. IIS listens for those requests, finds the files that match what was asked for, and sends them back. If someone requests your home page, IIS finds index.html (or index.aspx if you're using Microsoft's format) and sends it. If someone requests a page that doesn't exist, IIS sends a 404 error instead.

IIS can also run code on the server before sending the response back. If your site uses ASP.NET — Microsoft's framework for building dynamic websites — IIS runs that code, builds the page, and then sends the finished result to the browser. This is the same thing Apache does with PHP, but IIS does it with Microsoft's tools.

Why Windows hosting costs more than Linux hosting

The main reason IIS hosting is more expensive than Apache hosting is that Windows itself costs money. Your hosting provider has to buy a Windows license for every server running IIS. Linux is free, so hosting providers can offer Linux servers at lower prices. That cost difference gets passed to you in your monthly bill — Windows hosting typically costs 20 to 40 percent more than Linux hosting for the same amount of storage and bandwidth.

You're paying for the Windows license whether you use IIS-specific features or not. If your site is a basic HTML and CSS website, you could run it on either Windows or Linux for the same result, but Windows hosting would still cost more. That's why most small websites run on Linux — there's no reason to pay extra.

When you need IIS instead of Apache

You need Windows hosting with IIS if your website uses ASP.NET, Microsoft's web framework. ASP.NET only runs on Windows servers with IIS — you cannot run it on Linux. If your developer built your site in ASP.NET, you have no choice but to use Windows hosting.

You also need Windows hosting if your site uses Microsoft SQL Server as its database. SQL Server runs on Windows, though it can also run on Linux in newer versions. If your hosting provider offers SQL Server, they're running Windows servers, and IIS will be there too.

For everything else — WordPress, Drupal, static HTML sites, PHP sites, Node.js sites — Linux hosting with Apache or Nginx works fine and costs less. Your hosting provider will let you choose at signup, or will tell you which one they use.

How IIS differs from Apache in practice

Both IIS and Apache do the same basic job, but they handle some details differently. IIS uses a different configuration system than Apache — Apache uses text files you can edit directly, while IIS uses a graphical interface or XML files. If you're managing your own server, Apache is usually easier to configure because the settings are more readable.

IIS and Apache also have different default security settings and different ways of handling file permissions. A website that works perfectly on Apache might need adjustments to run on IIS, and vice versa. Your hosting provider handles these adjustments for you, but if you ever move your site from one to the other, you may need to ask for help with configuration.

Performance-wise, both are fast enough for most websites. The choice between them usually comes down to what tools your site uses, not which one is faster.

What you see in your hosting plan

When you're shopping for hosting, you'll see plans labeled "Windows hosting" or "Linux hosting". Windows hosting means IIS. You might also see "ASP.NET hosting" or "SQL Server hosting" — those are Windows plans too, just emphasizing what tools they support.

Your hosting control panel (usually cPanel on Linux or Plesk on Windows) lets you manage your site without touching IIS directly. You upload files, create databases, and set permissions through the control panel. IIS runs in the background doing the actual work of serving your pages.

Frequently Asked Questions

Can I run a WordPress site on IIS?

Yes, but it's not common. WordPress is built for PHP, which runs better on Linux. Some Windows hosting providers support PHP on IIS, but you'll find more WordPress hosting on Linux servers. If you're choosing hosting for WordPress, pick a Linux plan — it's cheaper and more widely supported.

What if my site is currently on Apache and I want to move to IIS?

You can move most sites, but it requires work. Static HTML sites move easily. PHP sites need to be rewritten in ASP.NET or another Microsoft language, or you need to find a Windows host that supports PHP. Your hosting provider can advise whether the move is worth the cost and effort.

Do I need to know how to configure IIS myself?

No. Your hosting provider installs and manages IIS completely. You manage your site through your control panel, and IIS handles the technical details behind the scenes. You only need to know about IIS if you're running your own server, which most website owners don't do.

Is IIS less find than Apache?

Neither is inherently more find. Both can be configured securely or insecurely. Security depends on how your hosting provider sets them up, what updates they explore, and what you do with your site. A reputable hosting provider keeps both equally safe.

What does IIS stand for?

Internet Information Server. Microsoft released the first version in 1995 as part of Windows NT. It's been updated many times since, and the current versions are much more capable than the original.