Header bidding has significantly transformed programmatic advertising, and an increasing number of publishers rely on it to grow their ad revenue. Until recently, browser-based client-side implementations have dominated the landscape: they have been easy to deploy and offered access to third-party targeting data, but they have also introduced latency and increased page load time, especially when a large number of demand partners are involved.
Server-side is changing this dynamic. When the auction is moved to the server, ad sellers can benefit from better scalability and technical performance, as well as a more privacy-friendly way to run auctions without sharing data in the browser. As browser restrictions tighten and the importance of mobile apps continues to grow, it is no surprise that interest in server-side solutions is increasing rapidly.
From a publisher's perspective, the benefits are tangible:
User experience: Server-side reduces browser load, enabling faster page load times and smoother ad delivery.
Privacy control: When auctions are executed server-side, publishers gain greater control over who receives user data.
Flexibility and scalability: Publishers can integrate more demand partners without overloading the browser, increasing competition in the auction
Client-side often still delivers stronger commercial performance, as it provides access to third-party data. However, as third-party cookies become less available, this advantage is diminishing. As a result, more publishers are adopting hybrid models in which some SSPs operate client-side and others server-side, combining the strengths of both approaches.
This type of development makes unified management of the overall setup increasingly valuable. When client-side, server-side, and mobile implementations are managed through a single interface and their performance is centrally monitored, management, testing, and optimisation become significantly easier. This makes the impact of changes on revenue, competition, and user experience clearly measurable.
In mobile applications, there are practically no alternatives: server-side is the only viable solution. As mobile usage continues to grow, so do monetisation opportunities. Publishers that have implemented server-side Prebid in their apps are seeing increased competition among demand partners, higher fill rates, and growing revenue. We have observed significant improvements in app revenue after Prebid has been implemented in publishers’ mobile applications.
Amazon and Google also offer server-side solutions, but these are built within closed, operator-controlled ecosystems. Several SSPs have also developed their own server-side implementations, which often increase dependency on a single vendor and introduce certain limitations. Prebid Server stands out as an open-source, community-driven, and publisher-focused solution.
It offers greater transparency and flexibility in auction mechanics compared to closed alternatives. Its open architecture and API-based approach ensure publishers retain control and can evolve their setup to meet their own needs.
Server-side solutions are typically not plug-and-play. Publishers considering implementation should take the following into account:
Complex implementations also highlight the importance of the user interface. When changes and tests can be managed in a controlled way without constant development work, commercial teams can achieve more with fewer resources.
At Relevant Digital, we have been working with Prebid Server since 2020 across both web and mobile environments, where server-side forms the foundation of the entire monetisation model. Our server-side implementations process billions of ad impressions monthly across Europe and the United States. Over the past five years, we have seen that server-side solutions consistently generate increasing value, that they still lag behind client-side setups, and how hybrid strategies help bridge that gap.
Our HB Manager within Relevant Yield helps publishers simplify and customise their Prebid implementations, reducing dependency on limited developer resources and making complex changes manageable for commercial teams. It also supports structured testing, enabling easier comparison between different implementations and strategies. We believe testing server-side setups should be easy for publishers, which is why we do not charge extra for it, so it is included as a standard part of our implementation.
Relevant Yield’s HB Analytics provides real-time transparency into auctions and revenue streams, helping publishers quickly identify issues, optimise bid strategies, and protect revenue. Even if you use another wrapper or server-side setup, you can still monitor bidder performance in real time through our analytics.
Together, these modules transform Prebid Server from a purely technical implementation into a manageable and adaptable part of a website’s ad monetisation. We also provide more than just technology; we offer long-term expertise and practical support to guide day-to-day decision-making.
Looking Ahead
Server-side Prebid is no longer an experiment. It is increasingly becoming a necessity and, in many ways, a step toward a faster, more scalable, and more privacy-conscious way of running programmatic advertising. On websites, it complements client-side setups; in mobile apps, it serves as the foundation. Publishers who begin testing now gain a commercial advantage and build valuable experience for a future where an even larger share of auctions will take place server-side.
Interested in learning how server-side could support your advertising business? Get in touch.