Understand Tracking Cookies and Different Domains
When there are multiple domains where a test needs to run or where the conversions need to be tracked, things get a little bit complicated. A common scenario would be the one where there's a main site that hosts all the products to be sold but the actual checkout happens on another domain.
In this situation, without forwarding the cookies to the checkout domain, the conversions will not be tracked accurately. Convert Experiments used to allow third party cookie to track conversions in these situations but those are not always allowed to be set by browsers.
On February 21st 2018, we disabled third party cookies, as more and more browsers seem to disable that by default and it adds privacy issues.
Mainly, there are two cookies that need to be passed as GET parameters:
- _conv_v - is the visitor level cookie that holds data that describe visitor's activity
- _conv_s - session level cookie;
They need to be passed in the URL as GET parameters, under the same names. To get their value, we make the following available:
Of course, the destination page needs to have convert experiment's code installed correctly for this to work.