PubNative’s Guide to Implementing sellers.json
What is it?
Sellers.json is the companion to app-ads.txt, which we introduced last year. As we recall, app-ads.txt and ads.txt are .txt-files uploaded to the publishers’ domain, storing the names of the publisher’s authorized sellers. Sellers.json is the equivalent list created by sellers, listing whose ad inventory they sell. SSPs and exchanges will store the following data about their inventory sources in a .json file which is connected to a company’s root domain (e.g. pubnative.net/sellers.json):
- name of the publisher (which can also be hidden on request)
- domain of the publisher
- account id and
- type of relationship
Sellers.json is not only closely linked to app-ads.txt, but also pchain and SupplyChain:
- pchain – Payment ID chain string; used to check for payment history, following the monetary transactions to check who gets paid and who was rejected payments; part of the new object introduced in the TAG Payment ID Protocol v1.0
- sellers.json – a file that allows the identity of the final seller of a bid request to be discovered (assuming that they are app-ads.txt authorized). It also allows all entities participating in the bid request to be discovered in the SupplyChain object. In order to use sellers.json, SupplyChain object has to exist in the BidRequest
- SupplyChain object – set of nodes, where each node represents an entity selling or reselling a given bid request; not part of the OpenRTB 2.5 protocol, but implementation advised by IAB
Why should you implement sellers.json?
If you’re already listed in app-ads.txt, you should use sellers.json to increase transparency in the SupplyChain, revealing all entities taking part in an auction process. This procedure allows DSPs to look up existing connections between sellers and their publishers, as long as both sides curate their respective documentations. Similar to DSPs looking up existing partnerships on app-ads.txt, the entries in sellers.json can be compared to the information provided in the Supply Chain object, in order to verify an existing relationship between publisher and seller.
How do you implement the sellers.json file?
Entities that are selling inventory from a publisher are expected to add the sellers.json file to their root domain and list all of the publishers they work with (e.g. http://pubnative.net/sellers.json). Along with setting up sellers.json, they would also upgrade their OpenRTB integrations to version 2.3 or higher to support the SupplyChain object.
The final buyer (DSP) can cross-check the information from SupplyChain with sellers.json file. It is expected that there is an entry in the sellers.json defining the relationship with the SSP or ad exchange and a publisher that should match the information listed in SupplyChain.
The following components should be found in the sellers.json file:
- identifiers, such as TAG-id
- version (currently: 1.0)
- sellers, incl. name, seller_id, seller_type, is_confidential, directness and domain
This is an overview of which information is passed between app-ads.txt, sellers.json, pchain and SupplyChain:
Check out IAB’s documentation and FAQ here for more detailed information on sellers.json. If you have any additional questions, drop us an email to firstname.lastname@example.org and don’t forget to have a read of our other posts.