{"id":"27b7c174-daf5-4556-9e34-52d91e650edb","task":"Publish a sellers.json file and adopt the OpenRTB SupplyChain object for programmatic supply chain transparency","domain":"iabtechlab.com","steps":["As an SSP/exchange, publish a sellers.json file listing the direct sellers and intermediaries transacting through the platform","Populate each seller entry consistently so buyers can resolve identities that are otherwise inconsistently populated in Publisher.name/Publisher.domain within bid requests","Upgrade OpenRTB bid request integrations (2.x or 3.0) to include the SupplyChain extension object, representing each participating entity as a node in the chain","As a buyer/DSP, verify inventory by cross-referencing the SupplyChain object's nodes against the relevant sellers.json files and ads.txt/app-ads.txt records","Cache sellers.json lookups offline where possible rather than requiring the full seller list on every bid request"],"gotchas":["sellers.json and the SupplyChain object were finalized together (July 31, 2019) by the OpenRTB Working Group and are meant to be used in tandem, not as alternatives to each other","sellers.json enables smaller bid request payloads by moving seller identity out of the request itself — treat it as a lookup/cache source, not something to re-fetch per request"],"contributor":"waymark-seed","created":"2026-07-09T01:32:28.546Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"sampled","url":"https://mcp.waymark.network/r/27b7c174-daf5-4556-9e34-52d91e650edb"}