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sellers.json & OpenRTB SupplyChain Object Specifications Made Available for Public Comment


NEW YORK, NY (April 11, 2019) – The IAB Technology Laboratory today has introduced for public comment two new technical specifications aimed at increasing trust of the digital advertising supply chain, specifically on the supply-side of real-time bidding and programmatic buying. The first new technology, sellers.json, enables buyers to verify the entities who are either direct sellers of or intermediaries in the selected digital advertising opportunity for purchase. The second, the OpenRTB SupplyChain object, allows buyers to see all parties who are selling or reselling a given bid request. The OpenRTB Working Group is seeking industry feedback during a 30-day public comment period, through May 10, 2019.

sellers.json and OpenRTB SupplyChain object serve complementary roles by extending transparency to supply-side platforms (SSPs) and exchanges. When finalized, the expectation is that SSPs and exchanges will post their sellers.json files for buyers to review. SSPs and exchanges would need to upgrade their OpenRTB integrations (on versions 2.x or 3.0) to include support for the SupplyChain object (an OpenRTB extension). Combining all of these standards and components will give advertisers and agencies the tools to understand what they’re buying, empowering them to be more confident and comfortable in their purchases.

These specifications were created by the IAB Tech Lab’s OpenRTB Working Group and build on the momentum towards transparency, brand safety, and trust in the digital advertising ecosystem brought by the ads.txt and app-ads.txt specifications. The ads.txt standard provides a mechanism for content owners to declare who is authorized to sell their ad inventory. For demand-side platforms (DSPs), it allows buyers to confidently purchase ads through approved seller accounts. Its companion, app-ads.txt, applies ads.txt functionality to ad transactions in mobile apps, as well as over-the-top (OTT) video apps. Together these two technologies increase transparency and are advantageous to buyers who want to protect their spend on open exchanges, and to publishers who benefit from programmatic sales.

“Growth in the global digital advertising ecosystem requires trust, and sellers.json and the SupplyChain object provide essential visibility into the supply chain, enabling buyers to curate media sources,” said Dennis Buchheim, Senior Vice President and General Manager, IAB Tech Lab. “Used together, these technologies help enable a more transparent, more efficient advertising environment. I encourage everyone to provide feedback to the Tech Lab, and adopt as soon as the specs are finalized.”

The two specs will also take centerstage in discussion at the upcoming IAB Tech Lab Innovation Day: Transparency and Securing the Supply Chain event in New York City on May 6th, 2019.

To review the new specs, go to Any comments or questions can be directed to and will be distributed to the working group for review.


About IAB Technology Laboratory
The IAB Technology Laboratory (Tech Lab) is a non-profit consortium that engages a member community globally to develop foundational technology and standards that enable growth and trust in the digital media ecosystem.. Comprised of digital publishers, ad technology firms, agencies, marketers, and other member companies, IAB Tech Lab focuses on improving the digital advertising supply chain, measurement, and consumer experiences, while promoting responsible use of data. Its work includes the OpenRTB real-time bidding protocol, ads.txt anti-fraud specification, Open Measurement SDK for viewability and verification, VAST video specification, and DigiTrust identity service. Board members include ExtremeReach, Facebook, Google, GroupM, Hearst Digital Media, Index Exchange, Integral Ad Science, LinkedIn, LiveRamp, MediaMath, Microsoft, Oracle Data Cloud, Pandora, PubMatic, Quantcast, Rakuten Marketing, Telaria, The Trade Desk, Verizon Media Group, Xandr, and Yahoo! Japan. Established in 2014, the IAB Tech Lab is headquartered in New York City with staff in San Francisco, Seattle, and London. Learn more at

IAB Media Contact
Laura Goldberg