Difference between ads.txt and sellers.json

Let’s explore the differences between Ads.txt and Sellers.json:

1. txt (Authorized Digital Sellers):
   • Purpose: Ads.txt is a publicly accessible file where publishers declare the authorized sellers who can sell their ad inventory. It helps combat ad fraud by ensuring transparency and authenticity in the programmatic advertising ecosystem.
   • Hosted Location: Publishers host the ads.txt file on their web servers, making it easily accessible for buyers to verify inventory authenticity.
   • Contents: Each line in the file represents an authorized seller, including the domain name and the publisher’s account ID associated with that seller.
   • Verification: Advertisers can check the ads.txt file to verify the legitimacy of sellers.
   • Example Line: If a publisher uses Google AdSense, their ads.txt might include:
   • com, pub-1234567890123456, DIRECT, f08c47fec0942fa0
     • com: Domain of the authorized seller (Google AdSense)
     • pub-1234567890123456: Publisher’s account ID
     • DIRECT: Indicates a direct relationship between the publisher and the seller

2. json:
   • Purpose: Sellers.json brings further transparency to the ecosystem. It is used by supply-side platforms (SSPs) and exchanges to list details about the inventory they can rightfully sell.
   • Hosted Location: Like ads.txt, sellers.json is publicly accessible and hosted by SSPs and exchanges.
   • Contents: It contains information about authorized direct sellers or intermediaries involved in real-time bidding.
   • Verification: Buyers can verify the final seller of a bid request, and publishers can check if an SSP is claiming an illegitimate relationship.
   • Example: If a buyer is offered inventory for “weatherbug.com” via an exchange platform called “abc exchange,” they can verify the inventory’s authenticity by checking if the publisher is listed on “abcexchange.com/sellers.json.”
3. OpenRTB Supply Chain Object:
   • This object helps identify all parties involved in a bid request. It contains nodes representing different participants in selling the bid request.
   • By combining ads.txt, sellers.json, and the OpenRTB Supply Chain Object, buyers gain clarity on authorized sellers, intermediaries, and the entire supply chain.

In summary, both files aim to enhance transparency in programmatic buying, but widespread adoption by publishers, SSPs, and exchanges is crucial for their success¹.