What is the _mkto_trk cookie?
This cookie is associated with an email marketing service provided by Marketo. This tracking cookie allows a website to link visitor behaviour to the recipient of an email marketing campaign, to measure campaign effectiveness.
Our October 2026 scan found it on 22 sites (1% of the 2,450 we scanned), set before any consent.
- Purpose
- Advertising
- Belongs to
- OneTrust
- Set as
- First-party (under the site's own domain)
- Typical lifetime
- 13 months (vendor says: 729 days) — shorter than the vendor documents
Sites that set _mkto_trk before consent
The highest-ranked 22 of 22 sites.
- amplitude.com5 tracking companies
- okta.com3 tracking companies
- trendmicro.com8 tracking companies
- box.com8 tracking companies
- washington.edu12 tracking companies
- auvik.com7 tracking companies
- conviva.com3 tracking companies
- alphonso.tv6 tracking companies
- sakura.ne.jp7 tracking companies
- hpe.com10 tracking companies
Show 12 more sites
- proofpoint.com3 tracking companies
- innovid.com3 tracking companies
- split.io9 tracking companies
- lww.com4 tracking companies
- redis.io12 tracking companies
- nokia.com5 tracking companies
- mountain.com11 tracking companies
- cvent.com5 tracking companies
- emarsys.net4 tracking companies
- mheducation.com3 tracking companies
- kaiserpermanente.org4 tracking companies
- prweb.com8 tracking companies
Related cookies
Other cookies from OneTrust.
- OptanonConsent384 sites
- OneTrustWPCCPAGoogleOptOut6 sites
- OTGPPConsent4 sites
How to stop it
Declining non-essential cookies in a site's consent banner should stop _mkto_trk 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.