ASP (Active Server Pages): what it is, how it works and how it differs from ASP.NET

ASP stands for Active Server Pages, a technology developed by Microsoft in 1996 for creating dynamic server-side pages. For web development with ASP technology, the website is written in Visual Basic Script or JScript (which is very similar to JavaScript but is Microsoft’s own version).

ASP is a server-side language: it runs on the web server, just before the page is sent over the Internet to the device that requested it.

Pages that run on the server can access databases, make network connections and perform other tasks to build the page the user will see. Only the resulting HTML code reaches the browser, which is why any browser can display the page.

How ASP works

1. The browser requests a page with the .asp extension.
2. The web server (IIS) runs the page’s code.
3. If needed, the code queries a database or sends an email.
4. The server returns only the resulting HTML to the browser.

Common tasks in ASP

ASP can run a range of complex server-side tasks, which makes it easier to build complete, high-quality web applications. Some of the most common ASP tasks and features include:

• Dynamic graphics generation.
• Development based on web forms.
• Accessing the server’s file system.
• Full database searches.
• Access to network services (HTTP/HTTPS).
• Simple error correction/debugging system.
• Sending emails via SMTP.

History of ASP

Microsoft released the first version of ASP in 1996, included at no cost with its IIS web server. At the time, ASP was based on VBScript (Visual Basic Script Edition), another Microsoft scripting language based on what was then its most popular programming language: Visual Basic.

Besides VBScript, ASP supports JScript, Microsoft’s version of JavaScript, and, with additional engines, other languages such as PerlScript or Python.

The successive versions of ASP.NET have kept improving this server-side web development technology. According to W3Techs, 4.2% of websites whose server-side language is known use ASP.NET (October 2026).

ASP today: ASP.NET and ASP.NET Core

ASP has evolved into its new version, ASP.NET, a free web framework for creating websites and web applications using HTML, CSS and JavaScript. It can also be used to build web APIs and use real-time technologies such as WebSockets.

Classic ASP.NET, on the .NET Framework, offers three frameworks for building web applications: Web Forms, ASP.NET MVC and ASP.NET Web Pages. Each of these frameworks lets you build web applications and is designed for a different development style.

Which framework to choose depends on your development experience, the type of application you want to build and the development approach you’re familiar with:

• Web Forms, for developers with experience in Windows Forms, WPF or .NET. It offers a rapid development style with a rich library of controls that encapsulate HTML markup.
• ASP.NET MVC, for developers with experience in Ruby on Rails and .NET. It focuses on full control over HTML markup, separation of code and markup, and easy-to-write tests. The best option for mobile and single-page applications (SPA).
• Web Pages, for developers with experience in classic ASP and PHP. It’s geared towards keeping HTML markup and code together in the same file.

Since 2016 there has been ASP.NET Core, the open-source version that runs on Windows, macOS and Linux. The latest stable version is 10, released in November 2025. It’s the choice for new projects: Web Forms only works with the classic .NET Framework, not with ASP.NET Core.

Differences between classic ASP, ASP.NET and ASP.NET Core

If your website still uses classic ASP, it’s worth planning the migration: in 2024 Microsoft announced that VBScript will no longer be enabled by default in Windows around 2027.

Other meanings of ASP

Outside web development, the acronym ASP also has other meanings:

• Application service provider: a provider of applications used over the Internet. It’s the predecessor of SaaS.
• Average selling price: the average price at which a product sells. It’s calculated by dividing revenue by units sold. More in price.

How Mailrelay helps you

If your website is built with ASP.NET, or any other technology, you can connect it to Mailrelay:

• Subscription forms with double opt-in that you can embed in any website.
• SMTP and API to send transactional emails from your application: confirmations, notifications or passwords. They’re included in the Standard and Enterprise plans, and you can try them for 30 days on the free account (see pricing).
• Webhooks that notify your application when someone subscribes or unsubscribes.
• Free account with up to 80,000 emails a month and 20,000 contacts for your newsletters.

Frequently asked questions

What is ASP?

It’s a Microsoft technology from 1996 for creating dynamic web pages. The code runs on the server before the page is sent to the browser.

What does ASP stand for?

In web development, Active Server Pages. In other contexts it can mean application service provider (a provider of applications over the Internet) or average selling price.

Are ASP and ASP.NET the same?

No. ASP.NET is its successor, from 2002, and runs on the .NET Framework. Today’s version is ASP.NET Core, which is open source and cross-platform.

Is classic ASP still used?

Some older websites still use it, but it only receives maintenance. It depends on VBScript, which Microsoft will stop enabling by default in Windows around 2027.

What language is used in ASP.NET?

Mostly C#. Classic ASP used VBScript or JScript.

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