What is the KTPCACOOKIE cookie?
KTPCACOOKIE is an HTTP cookie associated with PubMatic, a supply-side platform (SSP) that facilitates real-time bidding (RTB) auctions between website publishers and advertising buyers.
The cookie usually appears when a site displays ads delivered through PubMatic's ad chain or its partners, either directly from the pubmatic.com domain or through indirect integrations (cookie-syncing redirects) triggered by other ad-tech platforms on the page.
What data it stores
The cookie stores an identifier generated by PubMatic, used to recognize the visitor's browser within the ad-bidding infrastructure. The exact value format is not publicly documented and may vary.
Since it is set on the .pubmatic.com domain, the data is sent to PubMatic's servers (a US-based provider that is part of the global ad-tech ecosystem), not to the domain of the visited website.
What it is used for
For PubMatic, the cookie helps synchronize user identifiers across different advertising partners (cookie matching), a technical step required for RTB auctions to function correctly and to avoid showing the same ad repeatedly.
For the website operator, the presence of this cookie is a byproduct of integrating ads or advertising partners that rely on PubMatic's infrastructure, rather than something set directly by the site itself.
Does it require consent?
KTPCACOOKIE falls under the marketing/advertising category. Under the ePrivacy Directive (as implemented locally, e.g. Romania's Law 506/2004) and the GDPR, this type of cookie requires the visitor's prior consent before being placed.
Website operators must disclose this cookie in their cookie policy, correctly classify it as marketing, and ensure the script that generates it does not run before the visitor gives consent.
How to block or delete KTPCACOOKIE
- Visitors can delete or block this cookie from their browser settings (Chrome, Firefox, Safari, Edge – cookie and site data management section).
- Anti-tracking extensions or the browser's third-party cookie blocking mode can prevent it from being set.
- Site operators should automatically block PubMatic scripts (or the partner scripts that trigger them) until consent is obtained. A consent management platform such as CookieFix can do this automatically, halting marketing scripts until the visitor accepts that category.
Frequently asked questions
It's a marketing cookie set by PubMatic, a programmatic advertising platform, used to synchronize identifiers between ad partners involved in real-time ad auctions.
It doesn't store sensitive data like passwords, but it's used for cross-site advertising tracking, which is why it's classified as a marketing cookie requiring consent.
It typically lasts about 1 day before automatically expiring from the browser.
Yes. As a marketing/advertising cookie, under GDPR and applicable ePrivacy rules, explicit visitor consent must be obtained before this cookie is placed.