Pre-bid auctions (also known as “header auctions” or “header bidding”) run directly on a publisher’s page and allow publishers to access external demand that may not be available through their primary ad server.
The benefits of using Prebid.js to manage your header bidding partners are:
- How does it work?
- Step by step
- Further Reading
How does it work?
At a high level, header bidding involves just a few steps:
The Prebid.js library fetches bids from various partners
Prebid.js passes information about those bids (including price) to the tag on page, which passes it to the ad server as query string parameters.
The ad server has line items targeting those parameters.
Step by step
1. Call bidders asynchronously
- You configure Prebid.js and setup one or more supported “bidders” (SSP, retargeters, ad networks, etc. – whatever they’re called)
- As the page loads, Prebid.js will asynchronously call all bidders to request how much they’re willing to pay for the impression. Note: the asynchronous calls mean the pages’ content continues to render without interruption.
2. Timer on page
- To prevent header bidding partners from taking too long, Prebid.js enables you to set a timer to control how long the ad server should wait for the header bidding partners. If the header auction exceeds the timeout, the auction is skipped and the impression is sent to the ad server.
3. Ad server requests with key-value targeting
When bids are received, Prebid.js adds the price and creative identifier to your ad server’s call as a set of query string parameters.
4. Line items
Within your ad server, line items are setup to target the various bid prices, allowing the bidders’ programmatic demand to compete with other line items or integrated exchanges (like Google Ad Exchange) based on price.