Transfon
Since its launch in 2017, Ads.txt (Authorized Digital Sellers) has been a game-changer in fighting ad fraud and bringing transparency to programmatic advertising. It’s basically a way for publishers to publicly declare which companies are authorized to sell their ad inventory—helping advertisers avoid shady resellers and unauthorized middlemen.
But as ad tech has evolved, things have gotten more complicated. Many publishers now rely on third-party ad managers, and advertisers struggle to tell the difference between inventory sold directly by a publisher and inventory managed by someone else. That’s where the Ads.txt 1.1 update comes in, introducing two key fields: OWNERDOMAIN and MANAGERDOMAIN.
These fields add much-needed clarity by making it easier to see who actually owns a website and who’s managing its ad inventory. If you’re in the ad ops world, understanding and implementing these fields is crucial. Let’s break it down.
Both fields serve distinct purposes in identifying the key players behind an ad inventory source.
The OWNERDOMAIN field tells you who the actual parent company of a website is. This is particularly useful for advertisers who want to make sure they’re buying directly from the real owner—not some random reseller pretending to be legit.
Example:
OWNERDOMAIN=mywebsite.com
If a publisher owns multiple domains, all of them would point to the same OWNERDOMAIN.
The MANAGERDOMAIN field clarifies which third-party company is responsible for managing a publisher’s ad inventory. This is especially helpful when a site works with different ad managers across regions.
Example:
MANAGERDOMAIN=agency.com
Or, if different managers handle different markets:
MANAGERDOMAIN=agency-us.com, UK
MANAGERDOMAIN=agency-uk.com, US
The more complex programmatic advertising gets, the harder it is to verify whether an ad is being sold by an authorized seller. Without OWNERDOMAIN and MANAGERDOMAIN, advertisers can’t easily tell if they’re buying inventory from a direct source or through an intermediary. Here’s why that’s a problem:
By tying Ads.txt 1.1 together with Sellers.json and SChain, the industry gets a more complete picture of the ad supply chain—making fraud and misrepresentation much harder.
For advertisers, OWNERDOMAIN and MANAGERDOMAIN provide a much-needed trust signal. Here’s how:
Publishers should assess their setup:
Example for a website owned by Amprev.com:
OWNERDOMAIN=mywebsite.com
MANAGERDOMAIN=amprev.com
MANAGERDOMAIN=amprev.com, UK
MANAGERDOMAIN=amprev.com, US
The introduction of OWNERDOMAIN and MANAGERDOMAIN in Ads.txt 1.1 isn’t just a minor tweak—it’s a significant improvement for transparency in programmatic advertising. These fields help advertisers make better buying decisions, prevent fraud, and ensure that ad dollars go where they’re supposed to.
For publishers, properly implementing these fields means staying attractive to advertisers, reducing unauthorized resale, and maintaining trust in their inventory. As Ads.txt 1.1 adoption grows, these fields aren’t optional—they’re essential for any publisher serious about ad revenue and long-term sustainability.
Adstxt.dev is the best Ads.txt Manager for publishers and ad networks.