Sellers.json and SupplyChain Object : Specifications to help to see where inventory is coming from

You’ll be familiar with Ads.txt and App-ads.txt, which help sellers specify who their authorised digital sellers are. Well, now IAB Tech Lab are introducing SupplyChain Object and Sellers.json, specifications that together, will allow advertisers to see where the inventory they’re buying is coming from. The ultimate goal: to make the programmatic ecosystem more transparent and reduce the space for fraudsters.

In a programmatic transaction, a lot happens between the publisher owning the ad inventory and the DSP at the other end. An ad impression might first go to a header bidding wrapper on the server side, then different ad exchanges or an ad network before it gets to the DSP.

Ads.txt can provide information about inventory that’s sold direct, but it can’t identify all the intermediaries involved in the selling of ad space. But by using Ads.txt, OpenRTB SupplyChain Object and Sellers.json together, a buyer can see and verify all the different links in the supply chain.

What is OpenRTB SupplyChain Object? This object allows ad buyers to see all the entities which have been involved in the sale of the bid request. These entities are “nodes”, and the chain of nodes is discoverable. This means that the buyer can make sure that all the intermediary entities are ones they want to interact with. They can be used with OpenRTB 2.5 and OpenRTB 3.0.

What is Sellers.json? This file allows DSPs to see the last seller of a request (as long as the seller is Ads.txt-authorised). Basically, it’s the reverse of Ads.txt, which shows a list of authorised sellers on a domain. It also shows all the intermediaries participating in a bid request sale. Publisher name and domain attributes can be looked up and cached offline. Every seller has a seller_id, the same as the one appearing in the Ads.txt file, SupplyChain.nodes and usually in the property of an OpenRTB request

Ad systems will place their Sellers.json files on their root domain (for example, and IAB Tech Lab advises that all ad systems with an Ads.txt file should also publish and Sellers.json file on their domains.

What this all means

Essentially, these specifications build on the Ads.txt initiative, and allow a buyer to see the “chain of custody” for any given impression. The upshot of this is that it brings the ad-buying process closer to being fully transparent, making it harder to commit fraud in the programmatic ecosystem. With these three specifications, SSPs and DSPs and intermediaries can verify every node on an impression’s journey from publisher to buyer, helping them combat invalid traffic, ad fraud and counterfeit inventory.

The 30-day commenting period for both of these new specs will run until May 10, 2019, with IAB Tech Lab’s working groups looking for industry feedback up to this date.

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