Client-side header bidding and Google’s Open Bidding – a comparison

In May 2019 we published a blog entry where we covered building a connection between prebid.js and Google Ad Manager and compared it with Open Bidding (formerly EBDA). What remains unchanged is that Google’s Ad Exchange is still not compliant with prebid.js, so publishers using this header bidding standard have to link them with the use of a smart workaround. What has changed since then is that Google switched to a first-price auction (Unified Price Auction) and continues to push for their Open Bidding solution. In this article we would like to discuss whether Open Bidding is really a better solution than client-side header bidding.

Why Open Bidding?

Open Bidding belongs to the family of server-to-server solutions. It means that the auction between exchanges takes place in the back-end, on a server-side, which does not impact pages by any means. Publishers who use Google Ad Manager can leverage this feature to get additional demand from multiple external partners connected to Google’s platform with less effort comparing to prebid.js.

Theoretically, this approach can be more efficient, faster and easier to use. All the bidding happens outside of the browser, so there is no risk it negatively affects page load time, ad load time and user experience in general. It also does not require publishers to deal with typical to client-side header bidding implementation, which can be painful and time-consuming. Managing Open Bidding is also more friendly and does not require you to put any scripts on your website.

Why prebid.js?

As we already suggested in the past, even though Open Bidding was designed to be some sort of alternative to client-side header bidding and other server-side solution, we do not really see it this way. Actually, we highly recommend using it along with prebid.js as these two solutions work in a different way and do not interfere with each other. Also, there are some areas where prebid.js is still a more attractive approach.

First of all, Open Bidding unified auction is a feature of Google’s adserver and it is not fully transparent. Publishers as well as demand partners other than Google do not have full insight into details of an auction. And this is not the case when it comes to prebid.js. It is an open standard, which lets you access all the data regarding the bidding and fees, and gives you full control over the process.

Second, Open Bidding is not a plug & play solution either. A publisher needs to have direct relationships with all the exchanges they would like to activate, they also have to update their ads.txt files with Open Bidding-specific entries. Beyond that, it is necessary for them to work out the relevant setup in Google Ad Manager as it does not happen automatically.

Third, there is a big difference when it comes to third party exchanges. The number of bidders available through Open Bidding is limited, whereas the list of prebid.js-compliant platforms is long and fast-growing. It means there is more demand a publisher can tap into through prebid.js comparing to Open Bidding at least at this stage.

Given that, as long as you spend some resources on proper implementation or decide to work with an experienced partner, you can make prebid.js an extremely efficient solution. Still, it is worth to try running prebid.js and Open Bidding at the same time, as the latter does not cause any delays and hence may sometimes bring an added value. It also does not require any additional development, which makes it fairly easy to use.

What about Google’s first price auction?

Last but not least, Google’s Unified Price Auction has something to say too. The transition finished in late September (so it is too early for summaries), still an analysis of some websites from our portfolio led to a conclusion that at this stage Google’s move does not make client-side header bidding less useful. In some cases we also noticed that prebid.js revenues actually increased while Google revenues stayed at more or less the same level. Although it is not representative of the total inventory, it is certainly a clue regarding what the result of UPA for the sell-side of programmatic advertising may be.

To recap, prebid.js is still a strong header bidding solution and Open Bidding is not really a comprehensive alternative to it, even after the first-price auction was introduced. While Google is very likely to encourage giving up on prebid.js and moving to Open Bidding, there is a bunch of arguments against doing so.

If you want to know more about prebid.js, Open Bidding or programmatic in general, feel free to reach out to us at [email protected]

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