Ad Ops Decoder: What Is Header Bidding?

Header bidding is a way for publishers to solicit real-time bids from a multitude of programmatic partners on each and every piece of inventory by using the page header within a site's source code. Basically, it’s a convoluted way to bypass the ad server waterfall and ensure inventory is valued fairly in real-time.

It works like this:

  • A header partner integrates Javascript in the page header of a publisher’s source code; this code may exist by itself or be encapsulated in a wrapper with other header partners. 
  • When a user arrives on the page in question, the code calls out to the corresponding demand source (SSP, DSP, exchange) through the browser. (In desktop ad serving, the user’s browser is used as a communication hub for calls and redirects.)
  • The demand source launches an auction or auctions for some or all of the page inventory (depending on a publisher’s preferences) within the browser.
  • Winning bids are sent to the publisher’s ad server, where they are matched with the demand partner’s proper tags within “price buckets”—basically, giant sets of tags that cover a range of values, typically in $0.10 intervals.
  • The publisher ad server determines which source gets the honor of serving up its ad, but rather than static bid ranges, header bidding has introduced dynamic bids from demand sources that more accurately represent what buyers are willing to pay for a specific impression at that time.

The widespread adoption of header bidding has resulted higher CPMs for publishers, greater transparency in the programmatic market, an uptick in display PMPs, and the removal of intermediaries and arbitragers in programmatic trading. However, header bidding does increase the potential for latency by throwing auctions before the page loads. The auctions also weigh heavy on the browser and usurp a great deal of data, which can become a drawback on the mobile web.

AdMonsters Resources

AdMonsters Playbook: Header Bidding

The Tagless Option

Unwrapping Wrappers: A Conversation on Header Bidding With Index Exchange

Let the Right Ones In: Evaluating Header Partners

Header Tags in the Video Arena

What's Ahead for the Header

Rethinking the Ad Server

Ad Ops Decoder: What Is the Waterfall?

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Gavin Dunaway is Editorial Director of AdMonsters, heading up all website and print content as well as planning agendas for conferences like the Publisher Forum and Ops. Previously he served as Senior Editor for interactive advertising trade news depot, and before that he held reporting and editing roles for numerous industry-related publications. When not diligently producing news and feature articles related to ad ops, he enjoys playing guitar so loud that the walls shake. Follow him, if you dare, on Twitter at @AdMonsterGavin.

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