What Is Ads.txt

December 13, 2023 4 min
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Ads.txt (Authorized Digital Sellers) is a global market product launched by IAB Tech Lab in 2017 and aimed to protect customers’ money from fraudulent traffic. It is a text file stored in the website’s root folder containing the list of companies authorized to sell the inventory on the site. In other words, it quotes all the platforms allowed to sell the publisher’s inventory.

Why was ads.txt created?

The main reason why this technology appeared is the increasing cases of domain spoofing – a type of fraud that allows you to sell low-quality traffic by presenting it as premium.

This is how it happened: marketers paid for impressions on prestigious and expensive platforms, whereas they were displayed on cheap and low-quality resources. As a result, a lot of advertisers have found themselves deceived. In 2016, the last year before the introduction of ads.txt, around 16 billion USD was wasted on fraudulent traffic

How ads.txt works

Ads.txt helps partners verify the traffic purchase channels. Publishers, developers, webmasters, or media owners use an ads.txt or app-ads.txt (for mobile applications) file to list all the authorized traffic sellers. During the ad campaign placement, clients can compare seller IDs with the names from the ads.txt file on the site. If the file quotes the seller, the purchase is secure. If the name is not on the list, further transactions are risky. In reality, these days, no purchase takes place without an ads.txt or app-ads.txt file.

How to add ads.txt to your website

The procedure is quite easy:

  1. Create a simple text document;
  2. List all the verified sellers;
  3. Save the file and move it to the website’s root folder.

The list of authorized platforms should look like this:

  • Each line of the file should contain three mandatory fields with a comma between them;
  • The first line should name the seller domain;
  • The second line contains the Publisher ID (your website identifier on the seller’s site);
  • The third line states the relationship type of the publisher and the seller platform (Direct or Reseller). 

How to make ads.txt work

The file will work only provided there are no mistakes. To check for those, you can use special validators. You enter the URL address of the ads.txt to the validator (e.g. AdMob), and the software scans the document for incorrectly filled-in fields, faulty domain names, etc.

For mobile applications, there are only two requirements:

  1. The app should be registered on Google Play or Apple App Store.
  2. The app’s page in the store should list the developer’s website.

How to read ads.txt

Again, nothing complicated here. Just add “/ads.txt” to the website domain in the browser address bar, for example, “domain.com/ads.txt”. By reading the file, publishers can verify whether the platform selling the inventory from “domain.com” is one of the official sellers of this platform. If it is not on the list, there is a high chance that the inventory will be sold through domain spoofing.


Why ads.txt is helpful for both webmasters and publishers

The interests of advertisers are obvious – the technology allows them to obtain quality traffic. But what are the benefits for webmasters? One reason is that recently Google started disconnecting services lacking this file, which will definitely slow down inventory sales. Google takes into account the interests of advertisers that want to get the ad space they have paid for. Plus, if your website contains an ads.txt file, it protects you as a publisher from being added to the blacklist of advertisers.

Having said that, let’s sum up what each webmaster and developer should know about the ads.txt:

  • The technology provides transparency to the digital market and prevents fraud, thus raising confidence in programmatic purchases.
  • It directly influences monetization, as the published authorized list of sellers certifies your inventory. These days, marketers no longer buy ads without ads.txt.
  • A lot of demand-side platforms limit ad purchases through resources lacking ads.txt files or apps without app-ads.txt.
  • Ads.txt eliminates extra participants in the traffic purchase process and removes technological layers and partners. It significantly simplifies the process of purchasing and displaying ads;
  • It helps prevent sales of poor-quality inventory.
  • And finally, an important point for mobile app owners: app-ads.txt specification complements the ads.txt standard and enhances compatibility features to support displaying ads in mobile apps.

We hope that this article helped you understand the importance of having an ads.txt file on your website. If you are either a developer or a digital product owner, do not ignore this feature, as today, it is a serious and compulsory assistant in your inventory monetization.