Header Bidding
Header Bidding lets publishers offer inventory to multiple exchanges at once before the ad server call, increasing competition and yield.
Header Bidding is a programmatic technique that lets a publisher offer an ad impression to multiple ad exchanges simultaneously, before its primary ad server is called, so all demand sources compete in a single unified auction. It replaced the older "waterfall" model in which exchanges were called one after another in a fixed priority order.
How it works#
A small piece of code in the page header (historically using the Prebid.js framework) fires bid requests to several exchanges and Supply-Side Platform (SSP) partners at once. Each returns a bid via Real-Time Bidding (RTB). The page then passes the winning bids into the Ad Server, which runs the final decision against any directly sold campaigns and serves the highest-paying ad.
Why it matters#
In the waterfall, the first source that met a price floor won, even if a later source would have paid more, leaving revenue on the table. Header bidding makes every source bid against every other source on every impression, which typically lifts yield and gives smaller exchanges a fair shot at premium inventory.
The tradeoff is latency and page-weight: each header auction adds processing before the ad loads, so publishers tune timeouts and the number of partners carefully. Header bidding usually runs through an Ad Exchange layer connecting the participating buyers.
Related terms: Real-Time Bidding (RTB), Ad Exchange, and Supply-Side Platform (SSP).
