The title says it all. I'm looking for a good set of tools that I can use to load test a web application on IIS 7 before deployment.

3 Answers 3


There are a couple of good tools available:

Not free, but excellent if you are doing this professionally is Visual Studio Team System Test Load Agent. MSDN covers how to set it up and run it here: Controllers, Agents, and Rigs. You can download a trial here:

As far as free tools...

Web Capacity Analysis Tool (WCAT):

Overview: Web Capacity Analysis Tool (WCAT) is a lightweight HTTP load generation tool primarily designed to measure the performance of a web server within a controlled environment. WCAT can simulate thousands of concurrent users making requests to a single web site or multiple web sites. The WCAT engine uses a simple script to define the set of HTTP requests to be played back to the web server. Extensibility is provided through plug-in DLLs and a standard, simple API.


  • HTTP 1.0 and HTTP 1.1 capable
  • Supports IPv6 Multithreaded Support
  • Supports generating stress from multiple machines
  • Extensible through C plug-in
  • DLLs Supports Performance Counter integration
  • Measures throughput and response time
  • Supports SSL requests
  • NTLM Authentication request support
  • Easily supports testing thousand of concurrent users

Download the x86 version here, and the x64 version here.


I believe Apache Bench is pretty widely used for this sort of thing and can be used without any problem against other webservers. It's command-line based, so it should be pretty easy to script into your test suite or pre-deployment scripts.


  • ab is a good indicator but not much more. For real load testing you can't beat the 'web avalanche' appliance - you can rent them.
    – Rich
    Jun 2, 2009 at 14:43
  • AB was just what I needed, I was having SSL problems using WCAT, and couldn't get most other tools to work. Didn't care much about the load, just wanted it to generate a bunch of requests so I could test my server.
    – davenpcj
    Jul 31, 2011 at 0:17

I have used Web Application Stress Tool before. I'm wondering if this is a pretty standard tool to use, and if there are better alternatives

(WAS) can be downloaded here

There's also a kb article on how to install and use the application here

and a blog on how to use it here

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