What is the __adblocker cookie?
Set by some publishers' ad-blocker-detection scripts to remember whether an ad blocker was detected in the visitor's browser.
Our October 2026 scan found it on 15 sites (1% of the 2,450 we scanned), set before any consent.
- Purpose
- Functional
- Set as
- First-party (under the site's own domain)
- Typical lifetime
- Under a day
Sites that set __adblocker before consent
The highest-ranked 15 of 15 sites.
- independent.co.uk10 tracking companies
- onet.pl6 tracking companies
- jutarnji.hr10 tracking companies
- newsweek.com12 tracking companies
- slate.com20 tracking companies
- scmp.com17 tracking companies
- thehindu.com7 tracking companies
- tagesspiegel.de1 tracking company
- stuff.co.nz19 tracking companies
- salon.com6 tracking companies
Show 5 more sites
- archdaily.com4 tracking companies
- mainichi.jp30 tracking companies
- japantimes.co.jp32 tracking companies
- foreignpolicy.com22 tracking companies
- washingtontimes.com21 tracking companies
How to stop it
Declining non-essential cookies in a site's consent banner should stop __adblocker 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 written by CookieTosser, for a cookie the Open Cookie Database doesn't cover.
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.