Over 70% of publishers use header bidding to boost eCPMs, increase fill rates, and maximize revenues. While client-side header bidding is an overall improvement over the waterfall, there are a few drawbacks. To address these issues, a new technology emerged: server-side header bidding. A publisher can implement both, but which best fits your monetisation strategy?
Client-side header bidding
Client-side header bidding is a real-time competition between several demand sources that maximizes the number of demand partners bidding simultaneously on a publisher’s inventory. The process requires a wrapper that goes into a web page’s header, and the publisher selects how many demand sources to plug into the wrapper.
What are the advantages of client-side header bidding?
- Boost in RPM: In this real-time demand sources competition, supply-side and demand-side vendors can easily synchronise their cookies during the bidding process. This improved cookie matching allows advertisers to identify users more easily and retarget them to generate additional revenue.
- More transparency: Transparency is one of the key benefits of client-side header bidding. Publishers can access granular reporting to gain deeper insights about demand sources and clearing prices.
What are the drawbacks of client-side header bidding?
- Latencies: The biggest challenge with client-side header bidding is the potential latencies that can occur while loading ads and pages. This is usually due to the high number of SSPs competing in the header. These latencies can result in a diminished user experience.
- Complex set-up: Client-side header bidding is difficult to implement, manage, and optimize when you don’t have a dedicated technical team to do it. The setup requires implementing multiple demand source tags (one tag per page), so it usually takes a publisher over a month to get going.
- Limited ad requests: A browser can only perform a limited number of ad requests simultaneously, so only about a dozen can be sent from the client-side header bidding wrapper simultaneously.
Server-side header bidding
In server-side header bidding, the publisher chooses a server-side bidding technology partner to implement and host the solution. A single call is made from the web page to the third-party server, which continues making calls server-side to all integrated demand sources. The wrapper returns all bids and prices to the publisher, so pricing is highly transparent. This is especially great for mobile, where high bandwidth is necessary to sustain the connection and deliver the ads correctly. Several ad tech providers developed their wrappers; Google has Exchange Bidding, and Amazon has Amazon TAM.
What are the advantages of server-side header bidding?
- A solution for latency issues: With server-side bidding, the auction is managed on a 3rd party server. Slow loading times are much less of a problem, and user experience is improved.
- Why does it work better for Rich Media: Videos are often slow to load, so switching to server-side bidding greatly improves user experience. A server-side implementation is the only way to show ads on Over-the-top (OTT) devices.
- Unified reporting: The publisher will save time as he can monitor the performance of all its demand sources activated in unified reporting.
- Easy set-up: Compared to client-side header bidding, the technical setup is more straightforward; you must ask your server-side bidding provider to activate or deactivate your demand sources.
What are the drawbacks of server-side header bidding?
- Lack of control and transparency: Because the auctions are run on an external server, publishers and buyers are not privy to the details. There is no control over the priority ranking of demand partners, and any hidden fees that may be applied are invisible.
- No cookie matching: Most data is filtered out when moved to a server, so server-side header bids do not match cookies.
How to choose the right solution?
Unfortunately, there is no perfect header bidding solution. Both client-side and server-side header bidding have pros and cons. Study the advantages and disadvantages to determine which best fits your monetization strategy. Consider the type of inventory you have available, the current demand, and the up-and-coming marketing trends.
Relevant Yield
Relevant Yield is built with substantial hands-on experience in running programmatic ad operations. We are an independent company and a neutral, trustable and flexible partner. Our solution is highly customisable and continuously develops based on markets and customers' needs. Relevant Yield is the most comprehensive solution for ad ops and digital sales teams to maximise revenue. You will get an all-in-one package - revenue insights, real-time analytics and remote control of prebid setups.
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