If you’ve ever come across a file ending in .asp, you might wonder what it does. ASP stands for Active Server Pages. It’s a type of file used to make webpages dynamic, meaning the content can change based on user actions or server data.

These files are part of a web technology from Microsoft, created in the late 1990s. ASP files were often used to build interactive websites before modern frameworks like ASP.NET or PHP became common.

What Are ASP Files Used For?

ASP files are meant to run on a web server. They use server-side scripting to build webpages before sending them to your browser.

Instead of showing fixed text like an HTML page, an ASP file can:

• Display content based on user login or time of day
• Pull data from a database (like Microsoft Access or SQL Server)
• Handle forms, user input, or search functions
• Generate HTML dynamically on the server

When a user visits a page like example.com/page.asp, the server processes the code in the .asp file and sends back a regular HTML page to the browser.

ASP vs HTML: What’s the Difference?

HTML files are static. What you see in the code is what shows in the browser. ASP files, on the other hand, are dynamic. The server runs the code first, then sends HTML based on the result.

So:

• HTML runs on the client side (your device)
• ASP runs on the server side (the website’s server)

An ASP file might include code in VBScript or JavaScript to handle logic like user sessions or database queries. This code never reaches your browser — only the final HTML does.

How to Open or Edit an ASP File

If you have an ASP file and just want to read or edit the code, you can open it in any text editor. Some good options are:

• Notepad (Windows)
• Notepad++
• Visual Studio Code
• Sublime Text

If you want to run the file and see how it works, you need a web server that supports ASP. The most common option is IIS (Internet Information Services), which is built into Windows. ASP files won’t run in a browser directly like HTML—you need a server to process them first.

Can You Still Use ASP Files Today?

Yes, but they’re not very common anymore.

Classic ASP is now considered legacy technology. Microsoft still supports it for compatibility, and some companies still run websites or internal tools built with it. But for new websites, most developers use ASP.NET, PHP, or JavaScript frameworks like React or Next.js.

If you’re maintaining an old site or learning about older web systems, understanding ASP can still be useful.

Final Thought: Should You Use ASP Files?

ASP files were an important part of early web development, especially on Windows-based servers. They allowed sites to go beyond simple HTML by using scripts to generate live, changing content.

But today, Classic ASP is outdated. If you’re starting a new project, you should look into ASP.NET, Node.js, Python, or other modern tools. Still, if you’re working with legacy code or studying web history, ASP is worth knowing.

Still unsure about an ASP file you found? Leave a comment or share this with someone learning web development or maintaining old sites.