What is the ch_sid cookie?
We don't have a vendor description for this cookie yet, but our scan shows it's set by Piano, and it typically lasts under a day. It's listed as unclassified.
Our October 2026 scan found it on 5 sites (0% of the 2,450 we scanned), set before any consent.
- Purpose
- Unclassified
- Belongs to
- Piano
- Set as
- First-party on 40% of sites, third-party on 60%
- Typical lifetime
- Under a day
Sites that set ch_sid before consent
The highest-ranked 5 of 5 sites.
- cnbc.com9 tracking companies
- slate.com20 tracking companies
- entrepreneur.com7 tracking companies
- technologyreview.com6 tracking companies
- bostonglobe.com10 tracking companies
Related cookies
Other cookies from Piano.
How to stop it
Declining non-essential cookies in a site's consent banner should stop ch_sid 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.
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.