What is the _ym_uid cookie?
Used for identifying site users.
Our October 2026 scan found it on 107 sites (4% of the 2,450 we scanned), set before any consent.
- Purpose
- Analytics
- Belongs to
- Yandex.Metrica
- Set as
- First-party on 99% of sites, third-party on 1%
- Typical lifetime
- 12 months (vendor says: 1 year) — about what the vendor documents
- Where it's common
- 64% of the sites that set it use a .ru domain.
Sites that set _ym_uid before consent
The highest-ranked 30 of 107 sites.
- dzen.ru3 tracking companies
- kaspersky.com3 tracking companies
- mts.ru3 tracking companies
- ok.ru6 tracking companies
- timeweb.ru1 tracking company
- ivi.ru10 tracking companies
- bitrix24.ru3 tracking companies
- cdnvideo.ru2 tracking companies
- 2gis.com3 tracking companies
- globalsign.com3 tracking companies
Show 20 more sites
- rt.ru1 tracking company
- livejournal.com11 tracking companies
- pikabu.ru6 tracking companies
- tbank.ru4 tracking companies
- aparat.com3 tracking companies
- megafon.ru5 tracking companies
- rustore.ru2 tracking companies
- gismeteo.ru14 tracking companies
- rutube.ru1 tracking company
- beboo.ru3 tracking companies
- litnet.com9 tracking companies
- edna.ru1 tracking company
- playhop.com6 tracking companies
- jino.ru3 tracking companies
- varzesh3.com2 tracking companies
- haberler.com14 tracking companies
- ficbook.net1 tracking company
- sozcu.com.tr11 tracking companies
- max.ru2 tracking companies
- sondakika.com9 tracking companies
Related cookies
Other cookies from Yandex.Metrica.
How to stop it
Declining non-essential cookies in a site's consent banner should stop _ym_uid 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
- 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.