Ads.txt is an acronym for Authorized Digital Sellers. It is a file that publishers can use to declare which companies are authorized to sell their digital inventory. The ads.txt file is a simple text file that is placed on the publisher's website, and it lists the names and account IDs of the authorized sellers. This allows advertisers and other industry participants to verify the legitimacy of the inventory being sold, and helps to prevent the sale of counterfeit or fraudulent inventory.
Ads.txt was developed by the Interactive Advertising Bureau (IAB) in 2017 as a response to the growing problem of counterfeit inventory in the digital advertising industry. By using ads.txt, publishers can increase transparency and trust in the digital advertising ecosystem, and help to protect their brand and revenue.