Glossary
What is sellers.json?
Also called: sellers.json file
sellers.json is a public file an SSP or exchange posts to name the company behind each seller account ID that appears in publishers' ads.txt files.
हिंदी में पढ़ेंYour ads.txt lists account IDs, but it does not say who is behind them. sellers.json, another IAB Tech Lab standard, fills that gap. Each SSP and exchange posts the file on its root domain, with one entry per seller_id: the same ID that appears in your ads.txt line.
Each entry has a seller_type. PUBLISHER means the seller owns the site or app and is paid directly. INTERMEDIARY means it does not own the inventory, or is not paid directly. BOTH means it sells both kinds. The name and domain may only be left out when the entry is marked confidential.
Buyers use the two files together. A DIRECT line in your ads.txt should match a PUBLISHER entry in that SSP’s sellers.json, and its domain should match your OWNERDOMAIN. In IAB guidance, a seller whose domain matches neither OWNERDOMAIN nor MANAGERDOMAIN reads as a reseller.
Example
A bid request from ssp.example names news.example and seller account 4521. Check 1: news.example/ads.txt lists <code>ssp.example, 4521, DIRECT</code>. Check 2: ssp.example/sellers.json lists 4521 as News Example Media, seller_type PUBLISHER. Both match, so the buyer bids. A request naming account 9999 fails check 1.
Why it matters to publishers
When the two files disagree, buyers may treat a direct path as resold, or drop it. Spot-checking one ads.txt line against each SSP's sellers.json catches this early.