Client-side and Server-side : Make them work together

mardi 20 février 2024

In the dynamic realm of AdTech, the debate between client-side and server-side wrappers is taking center stage. Let's unpack the essentials. 🎭

Understanding the Basics: Client vs. Server

Before delving into header bidding intricacies, let's revisit the fundamentals. Your browser acts as the client, making requests to servers when you visit a site like The server (in the case Hubvisor’s hosting service) responds, delivering content to your browser.

The Era of Client-Side Header Bidding

Traditionally, publishers embraced client-side header bidding, integrating prebid JavaScript directly into web pages. This approach offers transparency and control, as prebid is being executed through their website. However, it comes with drawbacks like increased website latency and potential security concerns due to executing code directly on users' devices.

Enter Server-Side Header Bidding

Server-side header bidding shifts the action to a remote server.

The webpage just calls one external server, where prebid server is loaded. This minimizes website latency, enhances security, and accommodates an unlimited number of partners.

The reduced load on the client-side can significantly improve the user experience. However, transparency and control can be compromised, particularly due to cookie syncing challenges. But the biggest drawback (for now) of prebid server is cookie syncing.

By deporting prebid on an external server, you are cutting the ability for bidders to match with the publisher’s audience through 3p cookies. As a fix, publishers need to load one cookie syncing call per bidder so that cookie syncing works.

And this increasing the website’s load and latency, as well as introduce enormous discrepencies in terms of audience recognition. We believe that remote cookie syncing only works in 60% of the time. In short, server-side is 40% less efficient for bidders, because of 3p cookie syncing.

Why the Buzz in 2024?

This year, the impending demise of third-party cookies is reshaping the landscape. Server-side drawbacks related to cookie syncing calls are poised to fade away, making it a strategic choice for publishers. The ability to work seamlessly without reliance on third-party cookies positions server-side solutions as a forward-looking strategy.

The Hybrid Approach: Best of Both Worlds in the Post 3rd party cookie Era

With the impending end of third-party cookies, the hybrid approach emerges as a strategic choice. While server-side gains traction, client-side remains crucial, as not all partners are server-ready, and cookie recognition is more efficient on the client-side. Our recommendation? Go hybrid!

Maintain a core client-side system, leveraging its transparency and cookie recognition advantages. Simultaneously, integrate a parallel server-side setup to harness the benefits of reduced latency and enhanced security. This dual strategy ensures adaptability in the evolving AdTech environment, especially as the industry navigates the challenges posed by the cookie-less future.

Deep Dive: Key Considerations

  1. Impact on Site Speed: While server-side gains are often negligible compared to overall site loading, the user experience can be enhanced. We've conducted extensive tests, and you can explore our findings on

  2. Business Impact: Initial findings show varying results depending on setups. It's essential to understand how different configurations impact your revenue streams and business goals.

  3. Carbon Emissions: The environmental impact of client-side vs. server-side remains a gray area. We're collaborating with several carbon emission specialists to conduct a comprehensive analysis and gain insights into the real carbon footprint of both approaches.

  4. Productivity, Security, and Transparency: Server-side excels in immediate updates and security, but client-side retains transparency. Striking the right balance is crucial for a successful strategy. Share your thoughts and insights on these critical aspects!

Our verdict? It's not an "or" but an "and".

Final Thoughts

In this ever-evolving landscape, your strategy should be fluid. Conduct AB tests, avoid extremes, and stay informed. At Hubvisor, we're here to help you navigate the complexities of AdTech and unlock the full potential of your advertising strategy.

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Best, Hubvisor Team.

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