← Glossary
Header Bidding
Running multiple demand sources in parallel for the same impression instead of a sequential waterfall.
Header bidding lets a publisher solicit bids from multiple demand sources simultaneously for the same impression, then award it to the highest bidder — instead of checking each demand source sequentially in a waterfall, where a lower-priority source can win even if a higher bid existed elsewhere. In CTV, header bidding must happen server-side (not in a browser header, since there's no browser) ahead of the SSAI stitching deadline, which constrains it to a tight latency budget most web header bidding implementations don't have to meet.