Header bidding is one of the best innovations to hit the online advertising industry in the last decade. This revolutionary technology, which traditionally takes place on the client side/browser, paved the way for publishers to maximize their revenue and generate the most income possible from their programmatic ad inventory.
However, as it’s not a cut and dry solution there are some issues faced by publishers, especially when publishers decide to scale and increase their ad stack.
As more ad networks/bidders get added to their auction, the page load and site latency increase which harms the reader experience. The importance of ad ops teams finding the right balance between monetization and user experience goals, when optimizing publishing properties, becomes more prevalent.
Another advertising solution that publishers are adopting is a server to server header bidding auction. Server to server bidding or S2S refers to the process of a unified auction and bidding taking place on the server-side instead of within the client’s browser.
With S2S, the stress on the browser is alleviated by making a single call to a third-party server (i.e., Google DFP) and then to the existing demand partners of the publisher. Overall, the process saves more processing power, results in faster page loads which eventually improves the user experience.
However, server to server also has its pitfalls. One of the significant challenges faced is the cookie mismatch or cookie syncing latency. The majority of advertisers rely on cookies to target their intended customers which enables them to laser target their audience and maximize the ROI of their advertising campaigns.
Client-side header bidding does not face the same problem since the cookies are stored in the browser. Due to the lack of the S2S targeting mechanism for advertisers, CPM rates will be much lower compared to a traditional client-side header bidding set up.
Further evidence suggests that S2S technology might not be advanced enough yet to be used as a 100% solution. According to an article from Digiday, publishers who tested running 100% server to server header bidding did receive up to 40% increase in page speed, but with a decline of 25-30% decrease in ad earnings.
Suffice to say, S2S is still very much at the beginning stage of its life cycle and also struggles with low inventory fill and user match rates.
However, S2S is excellent for campaigns that require high viewability rates as ad rendering is much faster than that from client side header bidding. Informational campaigns targeting a general audience or video ads often deliver the best results with this setup.
As you can see, both client and server side bidding have their pros and cons. The best solution can be found in a combination or hybrid model of Server to server (S2S) and Client side header bidding.
An example can be using S2S for demand partners that have broader advertising goals like brand awareness, ad recall, etc. Then using client-side bidding for demand partners that are using cookies and visitor demographics to target their audience. Many publishers that start testing with S2S also keep their client-side header bidding partners to ensure that there is no loss of revenues when using S2S bidding.
With MonetizeMore’s header bidding solution, PubGuru, we can assist publishers in determining which advertising set up is best for your inventory. With PubGuru, publishers can run hybrid multivariate tests on their advertising partners to decide whether or not they run better as S2S or client-side bidders.