What is the tuuid_lu cookie?
This cookie is used by Eyeota as a third-party tracking identifier to uniquely recognize a user's browser, capture behavioral attributes across partner sites, and perform cookie syncing for targeted audience profiling and programmatic advertising.
Table of Contents
About tuuid_lu
| Vendor | BidSwitch |
|---|---|
| Category Category The functional category of the technology, such as Web Analytics or Social Media. Learn more | Advertising & Paid Media |
| Consent Category Consent Category The consent category this cookie most commonly falls under across sites we scan, normalized into four standard categories. Learn more | Targeting & Advertising |
| Prevalence | Very Common |
| Popularity Popularity Popularity is calculated from our dataset of 4.5B+ cookies analyzed across hundreds of millions of web pages. Learn more | Found on 10.8% of scanned pages |
| Expiration Type | Mixed |
| Party Type Party Type Whether the cookie is first-party or third-party. Learn more | 3rd-Party |
| Risk Level Risk Level Rates how sensitive the data stored by this cookie is (High, Medium, or Low) based on data classification and distribution. Learn more | Medium |
| Vendor Privacy Policy | https://www.bidswitch.com/privacy-policy/ |
| Vendor Website | https://www.bidswitch.com/ |
What is the purpose of tuuid_lu?
The tuuid_lu cookie is a third-party tracking cookie associated with BidSwitch (an IPONWEB technology; IPONWEB has been part of Criteo since 2022). The same cookie naming convention is also observed in conjunction with closely integrated ad-exchange partners such as Improve Digital (360yield.com), which is the most common initiator observed in this data set. It operates in conjunction with the primary tuuid (Targeting/Trading Unique User ID) cookie, which assigns a unique identifier to a user's browser. The tuuid_lu cookie specifically records the timestamp (lu = last update) of when this unique ID was last updated or synced across the programmatic advertising ecosystem. By syncing cookies with external Demand-Side Platforms (DSPs) and Supply-Side Platforms (SSPs), BidSwitch helps maintain accurate tracking profiles, coordinate programmatic bidding, and optimize ad frequency capping and retargeting efforts.
What are the Privacy Risks of tuuid_lu?
Risk Level: Medium
The tuuid_lu cookie is classified as Medium risk because it handles pseudonymous behavioral advertising data and cross-site tracking markers without transmitting any direct Personally Identifiable Information (PII). While observed natively as a third-party tracker (96.94%) that syncs user profiles across programmatic networks like Improve Digital and PubMatic, it only carries a 10-digit UNIX timestamp and technical sync status flags (|ix:0, |rp:0). Because it profiles user activity for targeted advertising but strictly lacks direct PII exposure, it perfectly fits the Medium risk criteria.
How to Remove tuuid_lu from a Website
To remove the tuuid_lu cookie, a website administrator must identify and remove the integration that triggers the BidSwitch user-sync pixel from their pages. In practice this means removing the BidSwitch tag or, more commonly, the upstream ad-exchange/SSP partner tag that initiates the sync (for this data set, primarily the Improve Digital / 360yield.com tag, as well as other programmatic partners such as creative-serving.com, company-target.com, mfadsrvr.com, and Market One/impact-ad.jp). Because the cookie is set as part of the cookie-syncing process that underpins programmatic bidding, it cannot be disabled independently of that functionality: if the programmatic monetization/bidding integration is required, the cookie cannot be fully removed without removing the partner tag(s) and the BidSwitch sync entirely. If the administrator does not control the partner integrations directly, they should contact the relevant ad partner or BidSwitch to have the sync disabled at the account/integration level.