How to know if any website is using Google Website optimizer for A/B testing? By viewing a source code. For what to look into view source which confirms that site is using Google Website optimizer

1 Answer 1


Look for the _utmx cookie for the site in question.

From Google

You can use Google Analytics with Google Website Optimizer (GWO), which is a tool that helps determine the most effective design for your site. When a website optimizer script executes on your page, a _utmx cookie is written to the browser and its value is sent to Google Analytics. See the Website Optimizer Help Center for more information.

  • NO _utmx in source code of website Commented Apr 24, 2012 at 2:40
  • And only these cookies are showing i.imgur.com/arEii.jpg no _utmx Commented Apr 24, 2012 at 2:43
  • It's possible they are using a different testing system like phpabtest or any of the many others. Commented Apr 24, 2012 at 7:20

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