Sellers.json and Supply Chain Transparency for Publishers

Programmatic advertising involves many companies between the advertiser and the publisher. To build trust, the industry created several transparency standards. You probably know ads.txt. Its companion, sellers.json, completes the picture.

What sellers.json is

sellers.json is a file published by ad systems, such as ad exchanges and supply-side platforms, at a standard location on their domain. It lists the accounts that sell inventory through that system and states whether each seller is a publisher selling its own inventory or an intermediary reselling someone else’s.

How it works with ads.txt

Your ads.txt file says: “These ad systems and account IDs are allowed to sell my inventory.” The ad system’s sellers.json file says: “This account ID belongs to this company, and it is a publisher or an intermediary.” Buyers can match the two to verify that an impression offered as yours really comes from you or from a partner you authorized.

The SupplyChain object

A third standard, the SupplyChain object, travels with each bid request. It lists every company that handled the request on its way to the buyer. Combined with ads.txt and sellers.json, buyers can see the complete path and avoid unauthorized or overly long chains.

Why publishers should care

• Better prices: many buyers prefer or require transparent supply paths and may bid less, or not at all, on inventory they cannot verify.
• Protection from fraud: it becomes harder for others to sell fake versions of your inventory.
• Clear relationships: you can see which partners actually resell your inventory.

Seller information visibility

Some ad systems let you choose whether your business name and domain appear in their sellers.json file. Google AdSense, for example, has a setting for seller information visibility. Making your information transparent can help buyers trust your inventory, though you should decide based on your own privacy preferences.

Practical steps

1. Keep your ads.txt limited to partners you actually work with.
2. Use the exact account IDs your partners provide.
3. Ask partners whether they are listed in their own sellers.json and how they appear.
4. Review your file every few months and remove old entries.

The big picture

Transparency standards reward honest publishers. When buyers can easily verify where their money goes, they are more willing to spend it. A clean, accurate setup is a small effort that supports your long-term revenue.