sellers.json

sellers.json is a JSON file an advertising system (SSP, exchange or reseller) hosts at /sellers.json on its domain listing the entities it sells for, so that buyers can discover whether each seller ID in a bid request's supply chain is a publisher, an intermediary or both, and who that entity is.

IAB Tech Lab maintains the specification on GitHub and describes the file's purpose as letting buyers "discover the entities that are direct sellers of, or intermediaries in, the sale of digital advertising"; it is designed to be cached offline so that bid requests stay small (IAB Tech Lab, sellers.json; sellers.json specification). Each seller record carries seller_id, seller_type (PUBLISHER, INTERMEDIARY or BOTH), name, domain and an is_confidential flag that lets a system withhold the name, which buyers increasingly treat as a reason to decline.

sellers.json and the SupplyChain object were designed together. Every SupplyChainNode has an asi (the advertising system's domain) and a sid (the seller's ID in that system); the buyer resolves asi/sellers.json and finds the record for sid. The node's name and domain are "omitted if it appears in the system's sellers.json" (OpenRTB 2.6, section 3.2.26).

Example:

{ "contact_email": "ops@ssp-a.example", "version": "1.0",
  "sellers": [
    { "seller_id": "pub-1001", "seller_type": "PUBLISHER", "name": "News Example Ltd", "domain": "news.example" },
    { "seller_id": "55521", "seller_type": "INTERMEDIARY", "is_confidential": 1 } ] }

Related: ads.txt, SupplyChain object, SPO, DPO.

Source: IAB Tech Lab, sellers.json specification.

1. IAB Tech Lab, sellers.json
2. sellers.json specification
3. OpenRTB 2.6, section 3.2.26