Glossarycookiesad targeting

Cookie Syncing

cookie syncingcookie matchingcookie mappingID syncingID matchinguser-ID mappingDSPDMPuser identifier

Also known as: cookie matching, cookie mapping, ID syncing, ID matching, user-ID mapping

Cookie syncing is the process of sharing a user identifier stored in a cookie between two or more platforms, allowing those platforms to exchange information about the same user. The primary goal is to improve ad targeting capabilities by ensuring that different systems — such as a DSP and a DMP — are working from a common understanding of who a given user is.

Because each platform sets its own cookies under its own domain, they cannot directly read one another's identifiers. Cookie syncing resolves this by mapping one platform's user ID to another's, enabling coordinated data exchange across the ecosystem.

How cookie syncing works between two AdTech platforms, for example, between a DSP and a DMP

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