Glossary
What is OWNERDOMAIN?
Also called: OWNERDOMAIN variable, owner domain
OWNERDOMAIN is an ads.txt 1.1 line naming the business domain of the company that owns the site, so buyers can match it to sellers.json.
हिंदी में पढ़ेंads.txt 1.1 added variables, and OWNERDOMAIN is one of them. It names the business domain of the company that owns the site or app, for example OWNERDOMAIN=northwind.example. It should equal the domain in your PUBLISHER entries in sellers.json, and the spec recommends it even when it is the same as the site’s own domain.
If the line is missing, the spec says to assume the owner is the domain being monetised. That causes trouble when one company owns several sites. Say Northwind Media owns news.example, but its sellers.json entries say northwind.example. Without OWNERDOMAIN the buyer assumes news.example, the domains do not match, and in IAB guidance the seller reads as a reseller.
MANAGERDOMAIN is different. It is optional and only for a seller that is not the publisher but is its primary or exclusive programmatic seller, such as a sales house in one country, with an optional country code. It is not a list of your SSPs.
Example
A media group runs 3 sites, all sold under the sellers.json domain northwind.example. Adding <code>OWNERDOMAIN=northwind.example</code> to each site's ads.txt is 3 lines in total, one per file. Without them, the DIRECT lines on all 3 sites can read as reseller paths.
Why it matters to publishers
One missing line can make direct inventory look resold, and resold paths are easier for buyers to cut. The fix is a single line per site.