Open auction inside a header-bidding wrapper
Watch a single impression go to auction in 120ms.
Prebid kicks off
Page loads pbjs.requestBids() with a 1200ms timeout across 8 bidder adapters.
When this breaks
Failure modes operators actually see. Tap one to read trigger, symptom, recovery, blast radius — then replay it in the sandbox to watch the message flow change.
Reshuffle for more — each fact links to its source.
Prebid.js's first public commit (2015) explicitly called out 'AdX's last-look advantage' as the reason header bidding needed to exist.
Around 2018–2019 most major SSPs flipped from second-price to first-price auctions — overnight breaking years of DSP bid-shading heuristics.
The US v. Google ad-tech case (2023) centers on whether AdX getting 'last look' inside DFP/GAM was an illegal tying arrangement — the open-auction step in this very scenario.