What is the tuuid_lu cookie?
Contains a unique visitor ID, which allows Bidswitch.com to track the visitor across multiple websites. This allows Bidswitch to optimize advertisement relevance and ensure that the visitor does not see the same ads multiple times.
Our October 2026 scan found it on 44 sites (2% of the 2,450 we scanned), set before any consent.
- Purpose
- Advertising
- Belongs to
- bidswitch.net
- Set as
- Third-party (under another company's domain)
- Typical lifetime
- 12 months (vendor says: 3 months) — longer than the vendor documents
Sites that set tuuid_lu before consent
The highest-ranked 30 of 44 sites.
- amazon.com33 tracking companies
- datadoghq.com14 tracking companies
- globo.com24 tracking companies
- amazon.co.za32 tracking companies
- livejournal.com11 tracking companies
- amazon.com.mx34 tracking companies
- instructure.com17 tracking companies
- terra.com.br23 tracking companies
- vnexpress.net14 tracking companies
- tenki.jp27 tracking companies
Show 20 more sites
- oricon.co.jp36 tracking companies
- haberler.com14 tracking companies
- syosetu.com24 tracking companies
- 24h.com.vn20 tracking companies
- goodreturns.in25 tracking companies
- kakuyomu.jp18 tracking companies
- chordtela.com34 tracking companies
- rambler.ru9 tracking companies
- animanch.com22 tracking companies
- politico.com31 tracking companies
- nielsen.com10 tracking companies
- hatena.ne.jp19 tracking companies
- hindustantimes.com36 tracking companies
- idnes.cz42 tracking companies
- asahi.com41 tracking companies
- ctvnews.ca38 tracking companies
- amazon.ae32 tracking companies
- xero.com18 tracking companies
- nicovideo.jp24 tracking companies
- lenta.ru9 tracking companies
Related cookies
Other cookies from bidswitch.net.
- tuuid52 sites
- custom_data22 sites
How to stop it
Declining non-essential cookies in a site's consent banner should stop tuuid_lu 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.