A question that regularly comes up in the Mercury Support forum is how to get a LoadRunner script to handle websites that require you to type in the characters from a picture of a funny-looking piece of text before you can perform an action such as creating a new account. “Surely someone has come across this before, and has figured out how to correlate these values?”

An example of a captcha

Well…uh…no they haven’t. These are Captchas – they are used to prevent bots from doing nasty things like signing up for thousands of Hotmail accounts or leaving comment spam. If it was possible to write a LoadRunner script that could handle these automatically, then they wouldn’t be very effective.

Automated solutions used by spammers revolve around text recognition software and are ineffective. A spammer might be happy with a 0.01% success rate when signing up for webmail accounts, but it is hardly useful to a load tester who wants a 100% success rate. Boing Boing’s solution is also not very useful for load testing.

If you need to load test a website that uses captchas, then the only practical solution is for the developers to include the captcha value somewhere in the web page that is presented to the user. You can then correlate the value the same way you would normally. Just make sure that the code that does this is removed before the website goes live.


Published On: March 6, 2006Tags: ,


  1. Chris Meisenzahl March 14, 2006 at 4:05 am

    I get a kick out of these things. When I need to use them for posting comments in places, they are sometimes so cryptic that I need 2-3 attempts at it doing it manually! 😉

  2. Stuart Moncrieff November 6, 2006 at 10:34 am

    This page is attracting a lot of comment spam, so I am closing off the comments option. If you have something to add, please email me (email address is on the front page of the website).


  3. Stuart Moncrieff February 22, 2007 at 11:24 am

    This idea tickled my funny bone: http://www.hotcaptcha.com/

    A CAPTCHA based on identifying attractive people…

Comments are closed.