What is the t3_sid_* cookie?
We don't have a vendor description for this cookie yet, but our scan shows it's set under the sites' own domains rather than by a third party, and it typically lasts 12 months. It's listed as unclassified.
Our October 2026 scan found it on 5 sites (0% of the 2,450 we scanned), set before any consent.
- Purpose
- Unclassified
- Set as
- First-party (under the site's own domain)
- Typical lifetime
- 12 months
- Name
- A family of cookies: the part after t3_sid_ varies by site or account.
Sites that set t3_sid_* before consent
The highest-ranked 5 of 5 sites.
- livejournal.com11 tracking companies
- rambler.ru9 tracking companies
- 2gis.ru5 tracking companies
- lenta.ru9 tracking companies
- sber.ru6 tracking companies
How to stop it
Declining non-essential cookies in a site's consent banner should stop t3_sid_* 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.
Understanding this page
- How cookie lifetimes work, and why a 13-month _ga matters
What a cookie's "expires" field actually controls, why Google Analytics ships a 2-year default that many sites cut down to 13 months, and how Safari's 7-day cap on script-set cookies changes the picture.
- First-party vs third-party cookies (and why "first-party" still tracks you)
What the distinction actually means technically, why browsers only block one of the two, and how CNAME cloaking, server-side tagging and cookies like _ga let sites keep tracking under their own domain.
- How to block or limit trackers
Browser privacy settings, content blockers, Global Privacy Control and clearing cookies compared honestly — what each one actually stops, what it doesn't, and what it costs you in return.