Tracking across multiple domains using matomo

We’ve the classic scenario of a customer who has his website split up into multiple domains (1 additional domain for every landingpage of their marketing campaigns, to "yield better click-through rates and google rankings). We tried to convince them that it’s much better for tracking, especially with the coming third-party cookie deprecation, to sum everything up under one domain - yet they want to stick to their pattern.

We first thought that this would be an issue, as matomo tracks (what we actually like a lot!) through first-party cookies by default, hence tracking across domains won’t work. Yet we’ve tested things and actually found that, if the same visitor visits different domains listed as the website aliases briefly one after the other, matomo seems to automatically merge these views into a single visit. Even before we’ve implement the proper js tracking code for cross-domain tracking according to

The only difference we can see is the added &pk_vid= URL parameter once we’ve added the proper js script for cross-domain tracking.

This just made us wonder; does matomo does any kind of cross-domain tracking by default? The only “custom” setting we’re using on our cloud instance is :


enable_userid_overwrites_visitorid = 0

Hi @fulstadev
user ID is not Visitor ID: