What is the uid cookie?
Contains a unique ID to identify a user.
Our October 2026 scan found it on 99 sites (4% of the 2,450 we scanned), set before any consent.
- Purpose
- Advertising
- Belongs to
- Adform
- Set as
- First-party on 11% of sites, third-party on 89%
- Typical lifetime
- 13 months (vendor says: 60 days) — longer than the vendor documents
Sites that set uid before consent
The highest-ranked 30 of 99 sites.
- samsung.com4 tracking companies
- medium.com2 tracking companies
- alibaba.com7 tracking companies
- drom.ru0 tracking companies
- globo.com24 tracking companies
- walmart.com2 tracking companies
- ivi.ru10 tracking companies
- indiatimes.com18 tracking companies
- techcrunch.com38 tracking companies
- usps.com24 tracking companies
Show 20 more sites
- pikabu.ru6 tracking companies
- nbcnews.com20 tracking companies
- costco.com3 tracking companies
- olx.com.br10 tracking companies
- terra.com.br23 tracking companies
- gismeteo.ru14 tracking companies
- vnexpress.net14 tracking companies
- savefrom.net1 tracking company
- mundodeportivo.com13 tracking companies
- jalan.net27 tracking companies
- tenki.jp27 tracking companies
- oricon.co.jp36 tracking companies
- haberler.com14 tracking companies
- syosetu.com24 tracking companies
- carsensor.net31 tracking companies
- 24h.com.vn20 tracking companies
- sozcu.com.tr11 tracking companies
- sondakika.com9 tracking companies
- immobiliare.it6 tracking companies
- shahvani.com1 tracking company
Related cookies
Other cookies from Adform.
- cid24 sites
How to stop it
Declining non-essential cookies in a site's consent banner should stop 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.