Visitor id not same in browser vs tracker debugger


I just want to wrap my head around the working. Visiting my website on icognito I see a certain visitor id using dev tools. Both in the calls and in the cookies saved by piwik. But these does not exist in the Tracker debugger. I manage to find my visit (I visit the website via a unique utm so I know it’s my visit) and then there is a visitor id that is completely diffrent from the one seeing in dev tools. How does this work? Does Piwik use fingerprinting somehow in these cases? so despite there not being a cookie in my device it still attributes it to my intitall visitor ID i had first time I visited? Anyone knows how this work or can point me to the correct article?

Hi there!

The ID visible in debug tools is the Cookie ID - the value saved in the _pk_id cookie, while the Visitor ID in our product is the actual Visitor ID, which can be calculated based on the Cookie ID and/or Session ID.

It can be different, because the actual Visitor ID also takes the Session ID into account.
The problem is - Cookie ID may still be called ‘Visitor ID’ in some places in our JavaScript Tracking Client. We are aware of that and we’re planning to simplify all of this a lot.

Here’s an article that goes into more detail on how Session ID works: What is a session and how is it counted? | Piwik PRO help center :smile: