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sellers.json explained: how it works with ads.txt

By the ads-txt.in team · Published November 8, 2026

If ads.txt is the publisher’s list of who may sell its ads, sellers.json is the ad system’s list of who its sellers are. Together, they let advertisers check both ends of a transaction.

What sellers.json contains

The IAB Tech Lab introduced sellers.json in 2019. Each ad system, such as an exchange or an ad network, publishes a file at its own domain, for example https://adsystem.com/sellers.json. It lists every seller account with fields such as:

  • seller_id: the account ID, the same one that appears in publishers’ ads.txt files.
  • seller_type: PUBLISHER if the account belongs to the site owner, INTERMEDIARY if it belongs to a company selling for others, or BOTH.
  • name and domain: who the seller is, unless the seller is marked confidential.

How buyers use both files

When a buyer receives a bid request, it can look up the seller account in the ad system’s sellers.json to see who owns it, and check the publisher’s ads.txt to confirm that account is authorised. If your ads.txt lists an account as DIRECT, the matching sellers.json entry would normally show it as a PUBLISHER account belonging to you. If you list it as RESELLER, it would usually be an INTERMEDIARY. Matching information builds trust; mismatches can make buyers cautious.

Google’s sellers.json

Google publishes a sellers.json file for its ad platforms. AdSense publishers can choose in their account settings whether their name is shown in it or kept confidential. Showing your business name and domain makes your inventory more transparent to buyers. Look under the account settings in AdSense for the seller information option.

What publishers should check

  • Every DIRECT line in your ads.txt should be an account you own.
  • RESELLER lines should come from partners you work with, copied exactly as provided.
  • Your seller information in each network should show the correct business name and domain if you choose to make it visible.

Do I need to create a sellers.json file?

Usually not. sellers.json is published by ad systems and intermediaries, not by ordinary websites. As a publisher, your job is to keep ads.txt accurate, which you can do with our validator and checker.

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