Server Side Header Bidding & taking the hybrid approach

Last updated: August 8, 2022 | by Aleesha Jacob

This post was most recently updated on August 8th, 2022

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. This blog post is going to explain how server-side header bidding works and its primary benefits. Stay tuned!

What is Server-Side Header Bidding?

Server to server bidding or Server-side header bidding (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 auctions moved to an external server instead of the user’s browser, page speed is positively affected, and publishers can leverage multiple ad exchanges, ad networks, and SSPs without compromising on user experience.

Ad networks, SSPs, and advertising exchanges usually go for client-side header bidding to conduct simultaneous auctions on the user’s browser, which can deteriorate page speed. Site speed can become a slow killer in the long term especially with publishers having lots of ad inventory.

Server Side header bidding originated to resolve the site speed issues that came along with client-side header bidding. In S2S, user browser congestion issues are diminished by calling Google Ad Manager and then to the publisher’s current demand partners. The benefits that come with S2S are faster page loads and an overall improved user experience.

Server-Side Header Bidding vs Client-Side Header Bidding

Unlike server-side header bidding, client side or browser side header bidding has auctions running in the user’s browser.

In both S2S and client-side bidding, publishers auction off their inventory to various demand partners which then place bids. The winning bid is the highest bid and the ad associated with that bid is served.

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.

Here’s why S2S header bidding is better than client-side header bidding:

  • Video: Publishers prefer S2S bidding over client-side when it comes to video content as it requires heavy processing power which can severely downgrade page speed. To cash out more from video content without compromising on UX , server side header bidding is the go-to for publishers.
  • Page Speed/ Site Speed: Client-side bidding relies on the user’s browser, hence it will slow the page speed down. The multiple ad slots and bids can lead to increased page loading times, affecting the user experience resulting in a higher bounce rate. By using S2S header bidding, however, the browser only needs to make one request to the ad server, which will process the auction and send the winning bid’s ad.
  • Best Bids: Browsers can make only a limited number of network connections at once, limiting your options for advertising partners. When server-side bidding is used, the server can send as many bid requests as possible without limitations. This ensures publishers get the best bids thus maximizing ad revenue.
  • Compatibility: In client-side bidding, both the audience and the publisher rely on the user browser for the auction procedure.The process doesn’t go smooth, if the browser isn’t upto date while in S2S bidding, the browser is used only to send requests to an external server, thus minimizing its need.

How Server-Side header bidding works?

Server Side Header Bidding & taking the hybrid approach MonitizeMore

As mentioned earlier, in S2S header bidding, bids are made on an external ad server unlike client side header bidding which leverages the user’s browser for auctions.

This is what happens in Server-Side Header Bidding:

  1. User enters URL to visit website and browser loads the page
  2. The header bidding script embedded in the site’s coding sends a request to the ad server 
  3. The server sends bid requests to ad exchanges, SSPs, and advertisers.
  4. During real-time bidding, the highest bidder wins the ad space
  5. The winning ad is served on the page.

How to select the best Server-Side Header Bidding Provider?

Despite server-side header bidding’s many features, it is important to choose a partner who will not only maximize your revenue but also make the process transparent and rewarding.

When choosing a server-side bidding partner, you should consider the following parameters.

  • Improved UX: If you choose a bidding solution, you should know whether your new partner’s solution will affect your site’s overall user experience. Even though the server-side process removes the dependence on the browser, it should be fast enough to ensure users do not experience latency when retrieving ads. Your metrics can be negatively impacted by prolonged delays and added latency.
  • Transparency: Making your auction transparent and fair is crucial to maximizing your revenue. You should choose a bidding solution that offers fair, transparent auctions, and does not charge you unnecessary fees (for example: high middlemen fees).
  • Revenue: For many publishers, revenue should be the primary factor when selecting an S2S bidding partner. In order to maximize revenue, the best partner should have premium advertisers who offer the highest rates for ad inventory, and the capability to match users to the right ads without affecting UX.

Server Side Header Bidding Cons

Server to server also has its pitfalls. One of the significant challenges faced is 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 setup.

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.

What to do now?

It is best to use a hybrid model that combines server-to-server (S2S) and client-side header bidding. S2S bidding can be used for demand partners with broader advertising goals, such as brand awareness.

Client-side bidding can then be used for demand partners who target visitors based on cookies and demographics.

It is common for publishers to keep their client-side header bidding partners when they begin testing S2S bidding in order to avoid any revenue loss.

With MonetizeMore’s header bidding solution, PubGuru, we can assist publishers in determining which advertising setup 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.

To find out more about MonetizeMore’s header bidding solution and how we can help you maximize your ad earnings, sign up today!

Server Side Header Bidding & taking the hybrid approach MonitizeMore

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