High Quality Content by WIKIPEDIA articles! Application Center Test (ACT) is a Microsoft load testing tool for web servers, focused on ASP.NET. It simulates numerous HTTP sessions from one machine. Using a bank of multiple computers, all firing off repeated HTTP requests, a significant load can be simulated. Tests can be written in either of the Microsoft scripting languages: VBScript and JScript. The tool can also be used for functional testing, although that is not what it is designed for. It also contains a recording function to create test cases without having to program them in.