What is the csync cookie?
Optimises ad display based on the user's movement combined and various advertiser bids for displaying user ads.
Our October 2026 scan found it on 19 sites (1% of the 2,450 we scanned), set before any consent.
- Purpose
- Advertising
- Belongs to
- Smartadserver
- Set as
- Third-party (under another company's domain)
- Typical lifetime
- 30 days (vendor says: 1 day) — longer than the vendor documents
Sites that set csync before consent
The highest-ranked 19 of 19 sites.
- amazon.com33 tracking companies
- amazon.co.za32 tracking companies
- uol.com.br17 tracking companies
- techcrunch.com38 tracking companies
- amazon.com.mx34 tracking companies
- gismeteo.ru14 tracking companies
- 24h.com.vn20 tracking companies
- indianrail.gov.in10 tracking companies
- chordtela.com34 tracking companies
- politico.com31 tracking companies
Show 9 more sites
- idnes.cz42 tracking companies
- amazon.ae32 tracking companies
- ynet.co.il23 tracking companies
- iqm.com14 tracking companies
- detik.com13 tracking companies
- kakaku.com22 tracking companies
- amazon.sa32 tracking companies
- eleconomista.es24 tracking companies
- theweathernetwork.com21 tracking companies
Related cookies
Other cookies from Smartadserver.
- pid29 sites
- TestIfCookieP18 sites
How to stop it
Declining non-essential cookies in a site's consent banner should stop csync 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.