What Is Server-Side Header Bidding & How Does It Work?

Updated on: January 2, 2024
Server-side header bidding enhances your website by enabling the highest possible yield with real-time auctions.

It isn’t fair to say that header bidding is still relatively new. However, it has been one of the most exciting, innovative, and disruptive advertising methods for publishers and advertisers alike. 

The technology is a widely adopted strategy for publishers to get a higher return on their ad inventory by allowing advertisers to compete in real time. Assuming you’re a publisher unfamiliar with server-side header bidding, I am here to help. 

In this post, I’ll explain the technology, how it works, and why you should explore using it. After reading this post, you should know how to implement a server-side header bidding solution for your ad inventories. So, shall we start?

What Is Server-to-Server Header Bidding?

Server-to-server header bidding (server-side header bidding or S2S header bidding) is a programmatic technique wherein the auction takes place on the ad server instead of the user’s browser. 

It lets you simultaneously work with multiple demand partners without compromising page speed. Google’s Open Bidding is a popular server-side header bidding solution. Let’s dwell more on it in the coming sections.

How Does Server-side Header Bidding Work?

Server-to-server header bidding works the same way as client-side header bidding; the only difference is that less implementation work is required. You must still put a JavaScript code in your header to send an ad request to your demand partner. Here’s a step-by-step explanation:

  • When a user visits a website, the JavaScript code between the head tag executes and sends a request to the server-to-server vendor.
  • The server will then send out bids to multiple demand sources.
  • Among them, whichever is the highest bidder will win, and the winning price is passed to the publisher’s ad server, i.e., Google Ad Manager.
  • This winning bidder will compete with the publisher’s guaranteed deals and Google Ad Exchange in the ad server.
  • The ad server selects the highest bidder and serves the ad to the users.

Benefits of Server-side Header Bidding

As discussed above, server-side header bidding is a great solution when you have a high volume of impressions and a higher number of demand sources that must compete for each impression. Let’s look at what it can do for you.

  • Reduced latency: Server-to-server header bidding is done in a server instead of a browser, reducing page load time. Although it varies just by a few milliseconds when compared with client-side header bidding, publishers still take page latency as an important factor as it affects the overall user experience.
  • Access as many demand partners: With server-to-server header bidding, you can send bid requests to as many buyers as possible. This increases competition and offers a better ad fill rate.
  • Perfect for video header bidding: Videos take longer to load on web pages than any other ad format. Serving video ads with the client side can damage the user experience. However, such complications won’t occur with server-to-server header bidding, and video header bidding will work perfectly.
  • No browser request limitation: Since web browsers have a limit to the number of requests they can generate, publishers that use client-side header bidding can only send a few ad requests during a session. At the same time, server-to-server header bidding remains unaffected by such problems since it doesn’t depend on the browser to send ad requests.

Challenges of Server-side Header Bidding

For years, server-side header bidding has been a popular topic in the ad tech industry. It’s a technology publishers use to reduce the latency associated with client-side header bidding. However, some challenges must be considered before implementing this technology. Here are the most common ones.

  • Potential for reduced transparency: The technology can lead to reduced transparency in the auction process, as bids are processed and filtered by server-side vendors and platforms.
  • Reduced ad relevance: Since server-side header bidding runs the auction on the server side, publishers cannot synchronize cookies with their demand partners and enable advertisers to serve personalized ads. This makes it difficult for publishers to improve their user experience and website performance.

Now that you know the technology’s pros and cons and wonder how to start the transition to server-side, read on to learn more about the factors you should be aware of.4

Best Practices for Implementing Server-Side Header Bidding

Server-side header bidding is an effective solution for publishers who want to monetize their inventory across multiple demand sources in real-time. The technology has many benefits, including receiving more demand, controlling auction dynamics, optimizing revenue, and reducing latency.

However, you should follow some best practices before implementing server-side header bidding on your site. Here are some that will help you maximize its effectiveness:

Choosing the Right Technology Partners

In the publisher ecosystem, there is no shortage of solutions that promise to improve yield and monetization. The ideal server-side header bidding provider should:

  • Offer a flexible technology platform that can be customized to meet different publishers’ needs.
  • Provide transparency into how its solution works and how much revenue it generates for publishers.
  • Be able to provide detailed information about how well the solution works across different types of inventory sources.
  • Demonstrating its ability to scale up quickly as new demand partners join them.

Testing and Optimizing the Setup

There are multiple ways to do it when setting up server-side header bidding. It is important to test your setup thoroughly before launching it in production. Test the setup of ads, demand partners, formats, etc., using a staging website to see how the setup performs within various scenarios (e.g., different browsers or mobile devices). 

You should also test latency and ad delivery performance across different devices and platforms. Here are some tips to help you optimize your server-side header bidding setup.

Monitoring and Analyzing Performance Metrics

The key to programmatic advertising success is understanding your inventory’s performance and how it’s changing over time. Publishers should closely monitor and analyze performance metrics such as bid rates, win rates, and revenue to identify areas for improvement and optimization. They should use data analytics tools to track performance and identify trends and patterns. Here’s a list of tools that can help you do the job.

Ensuring Compliance with Industry Standards and Regulations

As publishers move to server-side header bidding, they must ensure their setup complies with industry standards and regulations such as GDPR and CCPA.

They must also know the risk of using third-party vendors in header bidding setups. When vendors are involved, publishers need to understand how much data will be shared with each vendor and what kind of information these vendors collect through your website. Websites that fail to meet these privacy standards could see serious reputational damage and loss of revenue.


What Is Server-to-Server Header Bidding?

Server-side header bidding is a technology publishers use to reduce the latency associated with client-side header bidding. It involves moving the auction process from the user’s browser to a server, allowing faster and more efficient bidding.

How Server-Side Header Bidding Works?

In server-side header bidding, the ad requests are sent to an external server, which runs the auction on the server and returns the winning bid to the user’s browser. This process reduces the latency associated with client-side header bidding and allows for more efficient bidding.

What Are the Main Advantages of Server Sider Header Bidding?

The benefits of server-side header bidding include reduced latency, increased efficiency, and improved ad performance. It also allows more bidders to participate in the auction, resulting in higher bids and increased revenue for publishers.

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