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