To track visitors, Matomo (Piwik) by default uses 1st party cookies, set on the domain of your website. Cookies created by Matomo start with:
_pk_ses. When you use the Heatmap & Session Recording plugin, a cookie
_pk_hsr will be created.
When you exclude yourself from being tracked using the cookie method, Matomo will create a cookie
piwik_ignore set on the domain of your Matomo server (which might be a third party cookie if Matomo is setup on a different URL from the website being tracked).
Matomo by default does not use third party cookies but you can enable a third party
_pk_uid cookie it if you wish.
Learn more about What data does Matomo track?.
Default expiration times
The cookies described above will eventually expire and be removed from your users’ browsers. The default expiration times are listed below:
_pk_id– 13 months
_pk_ref– 6 months
_pk_hsr– 30 minutes