What is the tuuid_lu cookie?
tuuid_lu is an HTTP cookie associated with Improve Digital, a company specializing in programmatic advertising (ad exchange / supply-side platform) that brokers real-time auctions for ad space between publishers and advertisers/agencies.
The cookie typically appears on pages displaying ads served through Improve Digital's infrastructure, or through partner advertising platforms that integrate this provider as part of a cookie-syncing chain. It is not set directly by the site administrator, but by a third-party script loaded within the page's advertising context.
What data it stores
tuuid_lu generally stores a unique identifier generated for the visitor (an alphanumeric string or UUID), used to recognize them on future visits without containing directly identifying information such as name or email address.
The exact value format is not documented in detail publicly and may vary. The information is sent to Improve Digital's servers and, through the cookie-syncing process, may be shared with other advertising platforms in the bidding chain.
What it is used for
The main purpose is user-identifier synchronization (cookie matching) between Improve Digital and other demand-side/supply-side platforms involved in real-time bidding (RTB) for ad inventory.
In practice, the cookie helps build a browsing-behavior profile of the visitor, used to deliver more relevant ads and to measure advertising campaign performance across multiple websites.
Does it require consent?
tuuid_lu falls under the marketing category (advertising/tracking). Under the ePrivacy Directive (transposed in Romania via Law 506/2004) and GDPR, this type of cookie requires the visitor's explicit, prior consent before being set, since it involves cross-site tracking for advertising purposes.
- The site administrator must disclose the cookie in the cookie policy, including provider, purpose, and duration.
- The script that sets this cookie must be technically blocked until consent is obtained, not merely hidden from the banner.
- Refusing consent must be as easy as accepting it, per data protection authority guidance.
How to block or delete tuuid_lu
A visitor can manually delete or block this cookie via browser settings (Chrome, Firefox, Edge, Safari — per-site cookie management), or use dedicated ad-tracker blocking extensions.
For site administrators, blocking must be automatic and precede consent: a CMP platform like CookieFix can stop the Improve Digital script from loading and only activate it after the visitor accepts the marketing category, ensuring technical compliance with ePrivacy.
Frequently asked questions
No, it doesn't contain malware or sensitive data, but it is used for cross-site advertising tracking, which is why it's classified as marketing and requires consent.
It is set by Improve Digital, a programmatic advertising provider (SSP/ad exchange), usually via a third-party script loaded as part of an ad displayed on the site.
The typical duration is about 3 months, after which it expires automatically, though it can be renewed on a new visit if the visitor consents again.
Yes, since it's a marketing/tracking cookie, it requires the visitor's explicit, prior consent under Law 506/2004 and GDPR.