EBDA (Open Bidding) Explained

Also known as Open Bidding and Exchange Bidding for short, EBDA stands for Exchange Bidding in Dynamic Allocation. Essentially, Open Bidding is a server-side unified auction. This means the auction happens within the ad server and not the user’s browser. EBDA enables ad exchanges and SSPs to compete with Google’s own Ad Exchange (AdX) for impressions. 

It starts with the ad request, sent to Google Ad Manager (GAM) when a user visits the page and the at tag is triggered. A unified auction is then run to determine the best yield and display an ad. As simple as that sounds there are a few moving parts; 

  1. GAM needs to select the best line item by using a dynamic allocation from all of the available line items within GAM to compete in the unified auction;
  2. GAM sends a bid request to yield partners that are separated into yield groups (SSPs and Exchanges) ;
  3. An auction occurs between all targeted yield partners and the highest bid is returned to GAM;
  4. GAM hosts a unified auction between the AdX bid, yield partner bids, and eligible guaranteed line items via dynamic allocation, to select a winner;
  5. GAM then returns the assets and creative to the publisher to display the ad.


Historically, EBDA was created by Google in response to Header Bidding. The adoption of Header Bidding was driven by the promise of increased yields and reducing the influence of and in some cases reliance on Google AdX. 

Dynamic Allocation itself was a feature available for publishers within DFP to enable AdX to compete with a publisher’s own direct sales efforts. Adding Exchange Bidding effectively enables open auction to compete with guaranteed and remnant line items. Along with Google’s move to a first-price auction, this has helped create a more leveled playing field for the monetization of publisher inventory. Thus, going some way in restoring publisher confidence in working with Google.


In order to use Open Bidding (EBDA), a publisher must have an AdX account linked to GAM and ensure it is set to “default for dynamic allocation”. The publisher must get their Google Account Manager to sign an exchange bidding addendum with them, detailing payment terms and revenue share. Full Google Support is here

The next step is making sure you have demand partners enabled to be allocated into “Yield Groups”. To do this, your preferred demand partners must have a contractual agreement with Google. Within GAM you must select your partner from the list within “Companies” and tick “Enable for exchange bidding” and save.

To create a yield group you must go into the right area in GAM by selecting “Delivery” then “Yield groups” and select “Create a yield group” giving it an appropriate name. Here you can customize the yield group by choosing the ad format, environment, size, and targeting. Once satisfied you can click “Save” and “Activate” You should start seeing bids almost immediately. Full Google Support is here


Like most ad tech innovations, Open Bidding and Header Bidding were designed to achieve the age-old objective; the right message to the right person for the right price at the right time. One of the main differences between the two is that Open Bidding is controlled by Google and Header Bidding is controlled by the publisher. The main consideration here is that Google prioritizes PMPs and also decides the buyers who can compete with AdX. That being said, the relative ease in implementation as Open Bidding runs through Google’s Ad Manager infrastructure makes the whole process and management that much easier.

This brings us to another big difference; that Open Bidding does not happen within a user’s browser, it occurs within the ad server, GAM. Thus, combating the historic Header Bidding problem of page latency. 

Even with Header Bidding that is executed on the server-side, the reduction of page latency and increase in demand partner involvement is counterweighted by the issue around lower match rates. 

The Ad Tax conversation is also a consideration as Open Bidding also offers a lack of transparency. Demand partners pay a fee to participate per impression, which has led to tech vendors paying fees to other tech vendors to access EBDA. While publishers are unsure why a specific advertiser has won the impression as Google does not disclose the logic behind the dynamic allocation. 


As with most things in programmatic, there is no hard and fast or black and white answer. The truth is a combination of the two strategies a can compliment. Not one solution is better than the other, they only offer different roads to the same destination. Whether your technical capability is advanced or minimal, whether you place more importance on transparency, latency or control. 

As traditional Header Bidding occurs in the user’s browser before the unified auction within GAM through Open Bidding, there is an opportunity for both auctions to operate together. What is necessary is testing and isolation of inventory and line items to ascertain the best combination and set up. The idea at the end of the day and the aim of both technologies is to show the right user the right advert at the right time for the best value.