Understanding Sellers.json: A Comprehensive Guide to Transparency in Digital Advertising

Sellers.json is a file used in the digital advertising ecosystem to increase transparency by identifying the entities involved in the selling of digital advertising inventory. It is part of the OpenRTB (Open Real-Time Bidding) protocol and is maintained by the IAB Tech Lab. The file is typically hosted on a publisher's or supply-side platform's (SSP) domain and provides a publicly accessible list of authorized sellers.

Key Details of Sellers.json:

1. Purpose:

• Transparency: It helps buyers (advertisers, demand-side platforms, or agencies) verify the legitimacy of sellers and intermediaries in the programmatic advertising supply chain.
• Fraud Prevention: By listing authorized sellers, it reduces the risk of fraudulent inventory being sold.

2. Structure:
The sellers.json file is a JSON-formatted file that contains an array of seller objects. Each object represents a seller or intermediary and includes the following fields:

• seller_id: A unique identifier for the seller (e.g., a publisher or SSP).
• name: The name of the seller.
• domain: The domain of the seller's website.
• seller_type: Indicates the type of seller:
  • PUBLISHER: Direct seller of inventory.
  • INTERMEDIARY: An entity that resells inventory (e.g., an SSP or ad network).
  • BOTH: Acts as both a publisher and an intermediary.
• is_confidential: A boolean indicating whether the seller's identity is confidential.

3. Example of a Sellers.json File:

{
  "sellers": [
    {
      "seller_id": "12345",
      "name": "Example Publisher",
      "domain": "example.com",
      "seller_type": "PUBLISHER",
      "is_confidential": false
    },
    {
      "seller_id": "67890",
      "name": "Example SSP",
      "domain": "examplessp.com",
      "seller_type": "INTERMEDIARY",
      "is_confidential": false
    }
  ]
}

4. Hosting Requirements:

• The file must be hosted at the root domain of the seller's website (e.g., https://example.com/sellers.json).
• It should be publicly accessible and updated regularly to reflect any changes in authorized sellers.

5. AdX and Google's Requirements:

• Google AdX (Ad Exchange) requires publishers and SSPs to provide a sellers.json file to ensure transparency in programmatic transactions.
• Google also provides a tool called Ads.txt (Authorized Digital Sellers) that works alongside sellers.json to further validate sellers.

6. Relationship with Ads.txt:

• While ads.txt lists authorized sellers for a specific publisher, sellers.json provides a broader view of all sellers and intermediaries involved in the supply chain.
• Together, these files help buyers verify the legitimacy of inventory and reduce ad fraud.

7. Challenges:

• Accuracy: The file must be kept up-to-date to reflect current sellers and intermediaries.
• Adoption: Not all publishers and SSPs have fully adopted sellers.json, which can limit its effectiveness.

8. Benefits:

• Trust: Builds trust between buyers and sellers in the programmatic ecosystem.
• Efficiency: Streamlines the process of verifying sellers, reducing manual checks.

Conclusion:

Sellers.json is a critical tool for improving transparency and reducing fraud in digital advertising. By providing a clear list of authorized sellers, it helps buyers make informed decisions and ensures a healthier programmatic ecosystem. Publishers, SSPs, and other intermediaries should ensure their sellers.json files are accurate, up-to-date, and publicly accessible.