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10 September 2020

Ads.txt: what it is and how does it work

Ads.txt is an IAB-approved text file to combat fraud such as inventory arbitrage and domain spoofing. In order to clarify this concept, we answer a few questions below.

Ads.txt: what it is and how does it work

Over the years, the world of programmatic advertising has become increasingly crowded, with the multiplication of the different players involved in the advertising chain some problems related to transparency have arisen.

To combat fraud such as inventory arbitrage and domain spoofing, in mid-2017 the Interactive Advertising Bureau Tech Lab introduced ads.txt, a tool to protect ad inventory buyers from illicit sellers.

What is ads.txt and how does it work?

It is an IAB-approved text file that is intended to prevent unauthorized advertising inventory vendors. In fact, “ads” stands for Authorized Digital Sellers.

Publishers who monetize their site through adv will then have to upload this text file, containing all the partners authorized to sell the advertising inventory, in the root folder of the main domain, making it accessible via the url site /ads.txt. This way, buyers will be able to periodically check which are the authorized intermediaries and proceed with the purchase of advertising space in total safety.

What are the ways to check which sellers are authorized using ads.txt?

Let’s say you want to buy a banner on and want to make sure you go to authorized partners, just go to and check that the intermediary is in the list of sellers approved by the publisher.
Agencies, which need to check the validity of intermediaries from multiple publishers, use the crawler released by IAB Tech Lab to speed up this process.

Why is it important to integrate the ads.txt file?

To prevent the fraudulent sale of advertising space, which is one of the most important problems in the world of programmatic advertising. In fact, unless there is direct contact with the publisher, buyers have no way of knowing which SSPs are allowed to sell a particular publisher’s inventory and which are not, except through this tool.

Publishers who are part of the Stridely premium network receive assistance from our technical team, that will help them to upload the correct list of authorized sellers in the ads.txt file.

Are you a publisher and still have doubts about how ads.txt works? Do you want to submit your site and become part of our premium network optimizing your advertising revenue? Submit your site

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