The Prebid Timeout or BidderTimeout is a time limit on receiving bids from SSPs. This is how it works: a timer starts along with the Prebid auction, which is triggered by pbjs.requestbids. When that timer reaches the Prebid Timeout value, the auction concludes automatically even if not all requested SSPs have sent back bidResponses. Any SSP that has not sent a bidResponse within that time is considered to have timed out.
The timeout rate is the average rate at which an SSP times out. At Pubstack, we calculate the timeout rate for each SSP with the following formula:
# of times the SSP timed out / Total # of bid Requests sent to the SSP.
Having high timeout rates (> 10%) is detrimental to ad performances:
Thankfully, the fix is usually an easy one: a slight increase in the Prebid timeout configuration value can have a big impact on timeout rates.
The Prebid Timeout can be set up in the following ways:
pbjs.requestbids({ adUnitCodes: X, timeout: Y, bidsBackHandler: function () { Z }})
This can be a bit confusing to navigate. To eliminate any doubt, you can check the timeout value of your auctions with the AdWizard extension.
Well, as always, it depends. What your timeout configuration should achieve is both an auction that cannot be too long and a time limit that is not too restrictive for your SSPs. This is why it’s important to monitor the timeout rates of your SSPs to know if you are cutting off too many bids, or not. Usually, for European traffic, the best timeout is around 2000. This keeps timeout rates reasonable (usually <5%, at most 10%). You can go lower if you find that it does not increase your timeout rate significantly, or higher if, on the opposite, your SSPs are struggling to meet that limit, but there is rarely a need to go over 2500. It’s also a viable strategy to go for a different configuration on Mobile than Desktop, because SSPs tend to need more time to bid on Mobile. Some of our publishers experienced an increase in Prebid revenue of up to 8% simply by increasing their timeout from 1000 to 2000ms.
While the increase in revenue brought by tackling this issue may be quite meager, doing so is amazingly easy, resulting in a low-effort and guaranteed return on investment. Furthermore, beyond earning you additional revenue, fixing timeouts can also help decrease your dependency on GAM and increase the attractiveness of your inventory for SSPs.
After this introduction on timeouts, we invite you to continue your research by discovering and learning to solve a major timeout issue : Timeouts Simplified: How to avoid falling into the Dual Timeouts Trap
Once you’re done with both of our articles on timeouts, take a look at our Business Case : Timeouts optimisation and you should be good to go !