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CookieTosser

What is the __pat cookie?

This cookie stores difference between the client’s application time zone and UTC. At midnight, (application's local time), the previous visit is expired and a new one is created. The cookie is used for calculation.

Our October 2026 scan found it on 38 sites (2% of the 2,450 we scanned), set before any consent.

Purpose
Analytics
Belongs to
Piano
Set as
First-party (under the site's own domain)
Typical lifetime
30 days (vendor says: 30 days) — about what the vendor documents

Sites that set __pat before consent

The highest-ranked 30 of 38 sites.

Show 20 more sites

Related cookies

Other cookies from Piano.

How to stop it

Declining non-essential cookies in a site's consent banner should stop __pat being set on later visits. Blocking third-party cookies in your browser settings stops the third-party kind everywhere, and clearing cookies for a site removes any it already set.

Description from the Open Cookie Database (Apache 2.0).

Understanding this page