Programming ASP websites is made easier by various built-in objects. Each object corresponds to a group of frequently-used functionality useful for creating dynamic web pages. In ASP 3.0 there are six such built-in objects: Application, ASPError, Request, Response, Server and Session. Session, for example, is a cookie-based session object that maintains variables from page to page. Application Center Test is also available for load testing.

Most ASP pages are written in VBScript, but any other Active Scripting engine can be selected instead by using the @Language directive. JScript (Microsoft's implementation of ECMAScript) is the other language that is usually available. PerlScript (Perl) and others are available as third-party installable Active Scripting engines.

ASP has gone through four major releases:

* ASP 1.0 (distributed with IIS 3.0) in December 1996,
* ASP 2.0 (distributed with IIS 4.0) in September 1997,
* ASP 3.0 (distributed with IIS 5.0) in November 2000,
* ASP.NET (part of the Microsoft .NET platform) in January 2002 (the pre-.NET versions are currently referred to as "classic" ASP)
* ASP.NET version 2.0 (released on November 7th, 2005).

ASP.NET introduced the ability to replace in-HTML scripting with full-fledged support for .NET languages such as Visual Basic .NET and C#. In-page scripting can still be used (and is fully supported), but now pages can use VB.NET and C# classes to generate pages instead of code in HTML pages.