How Ads.txt Works

Since ads.txt was planned to be launched in 2017, its adoption rate in the entire digital publishing and advertising community has continued to increase, and the entire industry has felt its impact. In this article, we will discuss what ads.txt is, its benefits, and the best implementation practices we have learned since its inception.

What is ads.txt

Ads.txt is an initiative of the IAB Technology Lab to increase brands’ confidence in purchasing real publisher inventory and preventing Internet advertising fraud. According to the IAB, its mission is to increase the transparency of the programmatic advertising ecosystem. Download the complete video discovery guide.

Ads.txt stands for authorized digital sellers and is a simple, flexible and secure method that publishers can use to publicly declare which companies they authorize to sell their digital inventory. Its first version was available on June 27, 2017, and today more than 1.2 million domains are displaying the file.

Who benefits from ads.txt

Well, the entire programmatic ecosystem. Ads.txt can help publishers, advertisers, and everyone in between.

Publishers who implement ads.txt and advertisers who need it help the industry protect their advertising supply chain from fraudsters who try to impersonate the publisher’s domain and perform so-called pharming.


Domain spoofing is an act of misleading programmatic buyers to purchase hidden websites instead of the websites declared by the seller.

This happens when an imposter website provides its inventory as if it were an actual website, causing programmatic buyers to buy it instead of legitimate inventory.

Ads.txt overcomes this by submitting the website only to authorized sellers. Unfortunately, publishers that do not implement ads.txt may be blocked by most buyers who want to ensure that they only purchase authorized traffic.