Cookies and Sync 4 Browser Identity Browser ID Modules Prebid.js Demand Partners 1 Sync pixels 2 Cookie UIDs 3 Resolve EIDs 4 Bid + eids 5 Bids P_
Cookies and Sync Browser Identity 4 Browser merges two identity streams into user.eids 4 . Cookie sync 1 2 : each bidder reads its own UID via pixel redirect. ID modules 3 pull vendor UIDs from localStorage — cached IDs load sync; first visits race auctionDelay. Same UIDs feed PBS 10 server-side. FIELD NOTES → Cookie sync is per-bidder; ID modules produce universal IDs → Safari ITP caps JS cookies at 7d; localStorage survives → First visit = no sync = worst identity = lowest CPMs P_ atd.postindustria.com/4

How It Works

Browser merges two identity streams into `user.eids` [4]. Cookie sync [1] [2]: each bidder reads its own UID via pixel redirect. ID modules [3] pull vendor UIDs from `localStorage` — cached IDs load sync; first visits race `auctionDelay`. Same UIDs feed PBS {10} server-side.

Field Notes

  • Cookie sync is per-bidder; ID modules produce universal IDs
  • Safari ITP caps JS cookies at 7d; `localStorage` survives
  • First visit = no sync = worst identity = lowest CPMs

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