Menu Close

What Does ads.txt File Mean ?

ads.txt (Authorized Digital Sellers) is an initiative from IAB Technology Laboratory. It specifies a text file that companies can host on their web servers, listing the other companies authorized to sell their products or services. This is designed to allow online buyers to check the validity of the sellers from whom they buy, for the purposes of internet fraud prevention.

ads.txt file
ads.txt file

Introduced by the Interactive Advertising Bureau (IAB) in June of 2017, the ads.txt file is a list of authorised digital sellers (ADS) that are authorised to resell a website’s ad inventory.

Introduced to help combat the growing problem of domain spoofing in programmatic advertising, the primary goal of the file is to give buyers more confidence in the ads they purchase. Recently, a significant problem with programmatic ads has been the increase in fraudulent activity through fake domains. This problem has become apparent with the discovery of large-scale fraud networks such as Methbot and Hyphbot which used similar tactics to defraud advertisers out of millions.

How does Ads TXT work?

Ads.txt works by creating a publicly accessible record of authorized digital sellers for publisher inventory that programmatic buyers can index and reference if they wish to purchase inventory from authorized sellers. First, participating publishers must post their list of authorized sellers to their domain.

Any website can use an ads.txt file as long as they contain the correct information. Currently, the file must include the following information as outlined by the IAB:

  • Domain name of the advertising system or ad exchange
  • Publisher account ID
  • Type of relationship
  • Type of inventory

An example of a line in an ads.txt file would look like the following:, 3713, DIRECT #display

In this example, the subdomain has been authorised to display ads from the website hosting the ads.txt file. The publisher ID for the subdomain is 3713 with a direct relationship with the site. This usually means the relationship is direct and doesn’t involve any 3rd party exchanges or intermediaries. The final part of the entry is the type of inventory (ad) the website is using which is usually display, video or native.

All of this information is publically accessible by anyone who visits a website and can they can instantly see if another website has permission to display their ads. This becomes very helpful when fighting back against domain spoofing attacks where fake websites clone popular sites and try to sell their ad space.

The Benefits of ads.txt

With businesses losing billions of dollars to online fraud, the benefits of using ads.txt files are virtually endless. To give you an idea of some of the major benefits ads.txt files give to website owners, here are just a select few of the most significant benefits.

Easy to Install

The ads.txt file is incredibly easy to install on websites. Just like the robots.txt file, webmasters can copy the file over to their root domain which can easily be accessed on any web browser from any device.

Safe and Secure

Unlike other ad prevention methods, the ads.txt file is exceptionally safe and secure. Since it can only be uploaded by the owner of the website, there is no way to edit the contents unless you have the correct permissions.

Easy to Edit

Publishers can quickly and easily edit their ads.txt files by simply re-uploading them to the root domain. This means if they need to add new websites to the list, it can be done so with minimal effort.

As you can see from the benefits above, the ads.txt file is simple to install, easy to use and very secure. It’s no wonder organisations are pushing for it to become the new norm in programmatic advertising.




Leave a Reply