What is the _pctx cookie?
This cookie is required to sync different Piano product scripts containing common data points. It contains data from different products, for example for Composer Insights or Ad Revenue Insights, but only IF you have implemented any of these products.
Our October 2026 scan found it on 64 sites (3% of the 2,450 we scanned), set before any consent.
- Purpose
- Functional
- 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 _pctx before consent
The highest-ranked 30 of 64 sites.
- cnn.com5 tracking companies
- bbc.com4 tracking companies
- cnbc.com9 tracking companies
- npr.org9 tracking companies
- unesco.org2 tracking companies
- lemonde.fr2 tracking companies
- hbr.org12 tracking companies
- nbcnews.com20 tracking companies
- onet.pl6 tracking companies
- corriere.it12 tracking companies
Show 20 more sites
- elmundo.es20 tracking companies
- bfmtv.com2 tracking companies
- itmedia.co.jp9 tracking companies
- leboncoin.fr3 tracking companies
- fortune.com7 tracking companies
- actu.fr3 tracking companies
- meteofrance.com5 tracking companies
- nikkansports.com7 tracking companies
- dw.com0 tracking companies
- blic.rs8 tracking companies
- jutarnji.hr10 tracking companies
- variety.com9 tracking companies
- politico.com31 tracking companies
- rollingstone.com7 tracking companies
- slate.com20 tracking companies
- scmp.com17 tracking companies
- hollywoodreporter.com5 tracking companies
- entrepreneur.com7 tracking companies
- zeit.de2 tracking companies
- smh.com.au6 tracking companies
Related cookies
Other cookies from Piano.
How to stop it
Declining non-essential cookies in a site's consent banner should stop _pctx 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.