Another Bad Day for Ad Fraud – IAB Tech Lab Tightens the ads.txt Specification

This week, IAB Tech Lab announced an update to the ads.txt specification which has been widely adopted as an effective measure against ad fraud. The updated specification is now out for a 60-day public commentary period.

The update includes two new values for publishers to declare within their ads.txt files: 

  1. “ownerdomain” 

“ownerdomain” provides an important link between the business entity being paid and listed in a sellers.json file and the ads.txt file on the site being monetized.  

Specifying the domain of the business that owns the website that an ad is being served on helps to connect the seller domain for publisher entries in sellers.json files. Previously this has been hard to programmatically validate resulting in mismatched seller domains, particularly when an entity owns multiple publisher properties.  

  1. “managerdomain” 

This value helps increase the transparency into seller relationships via sellers.json and further strengthens ads.txt as a tool to reduce fraud in buying and selling of advertisements on websites, mobile apps and connected TV.

“managerdomain” enables the publisher to declare the primary or exclusive monetization partner of a given site’s inventory. This new addition to ads.txt will help to level the supply path optimization (SPO) playing field for small to medium publishers because those that outsource yield management and transact under their manager’s seller ids are automatically made to appear as though they have multiple hops to access their inventory. Historically, this has been a challenge for publishers when supply path optimization’s focus is on buying from the fewest number of hops in the supply chain to access inventory.  

The addition of the “managerdomain” will help buyers know that even with multiple hops, this may be the most optimal route to access that publisher’s inventory.  

“It’s another bad day for ad fraud, as IAB Tech Lab continues to enhance ads.txt to choke out bad actors,” said Sonia Carreno, President, IAB Canada “we continue to urge the industry to adopt these simple and effective measures to secure the supply chain for a sustainable future.” 

The public comment period for ads.txt 1.1 will run through May 31, 2022, after which the IAB Programmatic Supply Chain Working Group Ads.txt Subgroup, which developed the tool, will evaluate the comments received. It will then make any necessary revisions and release a final version. Comments are being accepted via email to:

If you are an IAB Canada member and would like to explore an IAB Tech Lab membership, please contact us at for a preferred member rate that can provide access to all IAB Tech Lab working groups and resources.