Which regex flavor does Matomo use?

I am trying to define a URL for Heatmaps, but Matomo tells me that my regex “does not have a valid format”.
Which regex flavor does Matomo, esp. Heatmaps, support?

Here is my regex:


As Matomo is written in PHP, it uses PCRE2.
So I think what you are missing is escaping the /.

Thanks for the quick response!
(I think the forum changed the regex I entered - is that possible?)
Not escaping the dot would not make the Regex fail, it would just match all characters where the dot is…

PCRE! For some reason, PCRE does not accept escaping the /, like I think did - althought the forum does not display it… :astonished:
This is what I had:

I had RegexBuddy convert it and now it works just fine: