# Header bidding: what it is and how it works · Zorraquino
> Header bidding lets a publisher offer each impression to several demand platforms at once before calling its ad server.
URL: https://www.zorraquino.com/en/dictionary/digital-marketing/header-bidding.html

# Header bidding

Header bidding is a programmatic advertising technique that lets a publisher offer its inventory to several demand platforms at once before calling its ad server

What it means, how it is used and where it comes up, with its related concepts.

[The whole glossary](https://www.zorraquino.com/en/dictionary)

## What it is and how it works

The name comes from its original implementation as JavaScript code in the page header, such as Prebid.js. As the page loads, several platforms bid simultaneously for each impression and the best offer then competes in the publisher's ad server. A server-side version also exists, reducing the load on the browser.

It emerged as an alternative to the waterfall, in which inventory was offered to buyers one after another in order of priority. It increases competition for each impression but can slow the page if poorly configured. It uses real-time auctions but is not a synonym for RTB or for programmatic advertising as a whole.

Also known as

Pre-bidding, Advance bidding

Topics

[Marketing and sales](https://www.zorraquino.com/en/dictionary/category/marketing-y-ventas)

## Related concepts

- [Programmatic advertising](https://www.zorraquino.com/en/dictionary/advertising/programmatic-advertising.html)
- [RTB](https://www.zorraquino.com/en/dictionary/advertising/rtb.html)
- [Ad impression](https://www.zorraquino.com/en/dictionary/advertising/impression.html)