Why Sellers.json Is Limited – And How Supply Chain Objects Can Help

Eric Bozinny, senior director of marketplace quality, PubMatic

The Sell Sider” is a column written by the sell side of the digital media community.

Today’s column is written by Eric Bozinny, senior director of marketplace quality at PubMatic

The IAB Tech Lab designed the sellers.json specification to follow the money. Sellers.json entries document payments as the supply chain moves from inventory source to buyer and payment moves from buyer to inventory source.

But sellers.json has its own limitations that require hygiene practices and general maintenance for accuracy. What’s more, just because an entry exists on sellers.json does not mean inventory is available to buyers. 

Unlike ads.txt files, of which there are hundreds of thousands, sellers.json files are only required for intermediaries. That’s a much smaller number. And, for anyone without access to supply-chain objects (SCO) or bidstream data, there is a tendency to assume that if an entry is on the sellers.json file, it must represent live inventory.

This, however, is not true. For truly 360-degree insight into the supply chain, SCO data is also essential.

SCO strengthens the supply chain

Every supplier, intermediary or buyer involved in a programmatic transaction needs access to SCO reporting to capture the supply-chain objects in bid requests. Since SCO serves as the key that ties together ads.txt and sellers.json data to a specific bid request, only then will there be full visibility (warts and all) into the path from the inventory source to the buyer.

But tapping into SCO isn’t exactly simple. While SCO acts as a key to provide context for ads.txt and sellers.json entries, its inclusion in the bidstream means users need specialized tools to extract it. As a result, those that have built up the necessary reporting and enforcement of SCO log files have benefited first.

Still, it’s worth the effort.

With the right infrastructure and technology, SCO can provide deeper insight into programmatic transactions.

For example, an outside observer may look at a sellers.json and ads.txt file to validate an inventory source. But SCO may also include a third node (or even a fourth or fifth – DV360’s SCO policy allows up to 10), revealing that the bid request is coming through multiple resellers.

When it works in conjunction with ads.txt and sellers.json, an exchange or DSP can confidently validate the sellers included in the supply path. SCO users get direct inventory, double confirmation of authorized sellers and can more easily spot an incomplete chain. 

Quality bids are a shared responsibility

Ultimately, stakeholders across the supply ecosystem need to take responsibility to ensure clean and accurate ads.txt and sellers.json files while passing full supply-chain object nodes upstream. Each intermediary and DSP must keep those downstream accountable by rejecting bids that don’t have supply-chain objects that meet the IAB Tech Lab specs.

Buyers must not only insist that sellers provide these three facets of the transparency window, but also use the data to reward supply partners who adopt and comply with these critical standards. 

Only then can the benefits of full transparency be realized and poor-quality supply be more easily identified and pushed out of the marketplace.

Follow PubMatic (@Pubmatic) and AdExchanger (@adexchanger) on Twitter.

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