What is the cX_G cookie?
This cookie is a Global ID mapping different IDs together into one ID. Used for building user profile information across all sites of a single customer where cx.js is implemented.
Our October 2026 scan found it on 29 sites (1% of the 2,450 we scanned), set before any consent.
- Purpose
- Advertising
- Belongs to
- Piano
- Set as
- First-party (under the site's own domain)
- Typical lifetime
- 13 months (vendor says: 13 months) — about what the vendor documents
Sites that set cX_G before consent
The highest-ranked 29 of 29 sites.
- cnn.com5 tracking companies
- cnbc.com9 tracking companies
- nbcnews.com20 tracking companies
- corriere.it12 tracking companies
- elmundo.es20 tracking companies
- itmedia.co.jp9 tracking companies
- fortune.com7 tracking companies
- nikkansports.com7 tracking companies
- blic.rs8 tracking companies
- jutarnji.hr10 tracking companies
Show 19 more sites
- variety.com9 tracking companies
- rollingstone.com7 tracking companies
- scmp.com17 tracking companies
- zeit.de2 tracking companies
- smh.com.au6 tracking companies
- technologyreview.com6 tracking companies
- asahi.com41 tracking companies
- thehindu.com7 tracking companies
- today.com19 tracking companies
- billboard.com9 tracking companies
- stuff.co.nz19 tracking companies
- politico.eu5 tracking companies
- boston.com11 tracking companies
- piano.io3 tracking companies
- archdaily.com4 tracking companies
- mainichi.jp30 tracking companies
- japantimes.co.jp32 tracking companies
- foreignpolicy.com22 tracking companies
- washingtontimes.com21 tracking companies
Related cookies
Other cookies from Piano.
How to stop it
Declining non-essential cookies in a site's consent banner should stop cX_G 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.