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Cookie Syncing

Tracking

Tracking Advertising ID Third‑Party Cookies Real‑Time Bidding (RTB)

Identifier matching between ad-tech parties to align user IDs across domains.

Definition

Cookie syncing (ID syncing) is a mechanism where two parties map identifiers to each other (often via redirects or pixel calls) so they can share audience profiles and bidding signals.

In plain English Identifier matching between ad-tech parties to align user IDs across domains.

Why this matters

Why it matters: It expands data sharing and increases the number of entities that can track a user.

Example

Example: Redirect chain passes partner ID in a URL parameter to create an ID map.