What is Header Bidding?
Header bidding is an advanced programmatic and ad server technique that serves as an alternative to the traditional “waterfall” method of working with multiple ad tags.
Header Bidding allows publishers to simultaneously offering ad space out to numerous SSPs or Ad Exchanges at once. Effectively, publishers use a Header Bidding Wrapper (typically JavaScript) that enables bid requests from multiple demand sources simultaneously using programmatic protocols such as OpenRTB. Integrations can be done client side or server side depending on the publisher setup or configuration.
The most popular Header Bidding wrapper is Prebid pioneered by Appnexus.