Two simple steps to protect yourself against bid caching

09/11 By Amanda Forrester

For many, bid caching is a problem that seemingly came out of nowhere, raising alarm bells across the industry. There are several tools, however, that can be used to address the varying implications for both publishers and advertisers. So what can you do to protect yourself?

Educate yourself

It’s important to first understand what bid caching is and to recognize the implications of the practice. Too often, the ad tech industry latches on to a black or white position on specific practices. While the lack of transparency of use in the case of bid caching is 100% wrong. It is possible that the negative impacts on brand safety were unforeseen negative results.

Bid caching is the process by which a programmatic buyer’s bid is stored during an auction (header, SSP, exchange) for use in subsequent auctions. In other words, when a buyer fails to win an impression, that bid is saved and applied to a later ad request. This, in turn, reduces the frequency of ad calls that header bidding creates thereby decreasing latency for buyers and improving their ability to forecast. It also increases yield, and in some cases price for sellers.

That said, this practice highlights the danger of creating opacity and implementing tactics without informing partners. In this instance, there is often a negative impact on inventory quality and price. Specifically, it impedes an advertiser’s ability to align with brand-safe content, and with a publisher’s ability to deliver ads in a brand-safe context.

Leverage the right tools


Leverage advanced reporting tools that block in real-time or implement granular spoofing reports to expose the URL you bid on and the URL that wins. This will allow you to identify potential cases of spoofing, caching, and publishers fulfilling demand on other inventory (either above board or via audience extension). In the case of bid caching, you’ll be able to identify mismatched bids, and you’ll be able to see if you’ve had any brand safety violations. It is possible that you’re winning ads that have been cached, and that there’s no risk to your campaign, which is why it’s important to maintain transparency. You should also review these reports with your suppliers to understand more about their practices and how they impact your campaigns.


Invest in an automated private marketplace (PMP) solution. Create direct programmatic deals with your advertisers to ensure higher yield, and prevent brand safety issues by utilizing media quality data directly within your ad server.

In the end, bid caching is simply another nuance of the ad tech industry. What’s important to remember here, is that the buy- and sell-side need to work more closely together and more diligently to strike fair deals which, in turn, will increase transparency. It’s easy to play the blame game, but in this fast-paced industry instead of focusing on blame, we should focus on solutions. This is why it’s important to choose partners that provide transparency within all of your transactions.