What is the demdex cookie?
Unique value with which Audience Manager can identify a user. Used, among others, for identification, segmentation, modeling and reporting purposes.
Our October 2026 scan found it on 108 sites (4% of the 2,450 we scanned), set before any consent.
- Purpose
- Advertising
- Belongs to
- Adobe Audience Manager
- Set as
- Third-party (under another company's domain)
- Typical lifetime
- 6 months (vendor says: 180 days after last activity or 10 years when opting out) — about what the vendor documents
Sites that set demdex before consent
The highest-ranked 30 of 108 sites.
- amazon.com33 tracking companies
- digicert.com1 tracking company
- oracle.com2 tracking companies
- ibm.com2 tracking companies
- dnsmadeeasy.com1 tracking company
- avast.com5 tracking companies
- hostgator.com3 tracking companies
- go.com3 tracking companies
- paloaltonetworks.com2 tracking companies
- amazon.co.za32 tracking companies
Show 20 more sites
- docker.com3 tracking companies
- mysql.com1 tracking company
- target.com5 tracking companies
- loc.gov1 tracking company
- redhat.com1 tracking company
- elpais.com7 tracking companies
- box.com8 tracking companies
- prnewswire.com13 tracking companies
- usps.com24 tracking companies
- hbr.org12 tracking companies
- nbcnews.com20 tracking companies
- worldbank.org9 tracking companies
- bankofamerica.com3 tracking companies
- fidelity.com15 tracking companies
- corriere.it12 tracking companies
- costco.com3 tracking companies
- as.com7 tracking companies
- hotpepper.jp13 tracking companies
- itmedia.co.jp9 tracking companies
- gazzetta.it7 tracking companies
Related cookies
Other cookies from Adobe Audience Manager.
- AMCV_*111 sites
- AMCVS_*84 sites
- s_cc74 sites
- dpm69 sites
- everest_g_v259 sites
How to stop it
Declining non-essential cookies in a site's consent banner should stop demdex 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.