ads.txt 1.1 blog post cover

Ads.txt 1.1 Update – What Is ads.txt And Why Should You Use It


Ads.txt is a file that lives on your web server and tells programmatic buyers which inventory sources are authorized to sell your ad space. The IAB Tech Lab launched ads.txt in 2017 to combat ad fraud and increase transparency in the programmatic advertising ecosystem. In August 2022, ads.txt 1.1 was introduced - an updated version that offers more protection and security for buyers and sellers.

If you're a web publisher, ads.txt is essential to ensure that your ad space is only being sold through authorized inventory sources. In this blog post, we'll give you a brief overview of what ads.txt is and why you should use it.

What Is Ads.txt?

Ads.txt stands for Authorized Digital Sellers and is a file that tells programmatic buyers which inventory sources are authorized to sell your ad space. If you're a web publisher, you can use ads.txt to white-list the demand-side platforms (DSPs), ad networks, and other ad tech companies authorized to sell your ad inventory.

The goal of ads.txt is to combat ad fraud and increase transparency in the programmatic ecosystem. By white-listing authorized sellers in an ads.txt file, publishers can take back control of their inventory and prevent bad actors from selling counterfeit or pirated inventory under their domain name.

What Is Ads.txt 1.1?

Ads.txt 1.1 is a long-awaited industry-wide update that The IAB Tech Lab released in mid-2022. This new ads.txt version clarifies the relationships in the supply path between publishers, demand partners, and intermediaries. Ads.txt 1.1 was created to protect advertising inventory hosted by publishers by allowing inventory owners to declare authorized sellers, making it harder for fraud or inaccuracies to damage supply chain transparency.

The primary change in ads.txt 1.1 is the addition of two new values - OWNERDOMAIN and MANAGERDOMAIN. This change in ads.txt is a simple update but one of very high importance:

  • OWNERDOMAIN is the domain name of the company that owns the inventory.
  • MANAGERDOMAIN is the domain name of the company that manages the inventory on behalf of the owner.

Adding these two fields helps improve transparency and trust in digital advertising by helping to ensure that buyers are buying inventory from authorized sellers.

How Does Ads.txt 1.1 Work?

When ads.txt is implemented, programmatic buyers can only purchase ad inventory from the sources listed in the ads.txt file. This helps to cut down on domain spoofing, as well as inventory seller mismatches. Ads.txt also allows for greater transparency into the relationships between publishers, sellers, and buyers.

Ads.txt files are hosted on a publisher’s server and contain a list of all the companies authorized to sell their ad inventory. The ads.txt file is freely available to anyone who wants to access it, and you can check to see if a website has an ads.txt file and view its contents by adding /ads.txt to the end of the root domain, e.g., https://morewords.com/ads.txt

Ads.txt files are updated in real-time, which means that changes can be made quickly and easily as relationships between publishers, sellers, and buyers change over time.

When a buyer wants to purchase ad space on a publisher's website, they'll first check the publisher's ads.txt file to see which sellers are authorized to sell that particular ad space. If the buyer doesn't see the seller they want to purchase from listed in the ads.txt file, they'll know not to purchase that inventory as it could be counterfeit or pirated.

Ads.txt Example

Ads.txt files are written in plain text and with comma-separated syntax. At the top of the page, you can find information about the website and which ad tech company serves the ads, including the two variables OWNERDOMAIN and MANAGERDOMAIN as specified with the ads.txt 1.1 version update.

ads.txt new variables

Further down, you will find a long list with more information about the various advertising partners that are connected to the domain. Each line represents an ad tech company and includes useful information such as the partner's name, account ID, and relationship type.

ads.txt example

Let us break down the different elements of a line item to give you a better understanding of what purpose they serve:

PlatformX, 12345, DIRECT, a123b4567cd891ef # display

  • PlatformX - This is the advertising technology platform through which the publisher sells their inventory.
    12345 - This is the unique Seller Account ID that each publisher receives when they open an account with a vendor. During header bidding auctions, advertisers use this ID to authenticate publishers.
  • DIRECT/RESELLER - Direct or Reseller indicates whether the publisher sells their inventory through direct programmatic deals, or whether the publisher has permitted another company (an ad network or digital advertising agency) to sell its inventory on its behalf.
  • a123b4567cd891ef - This optional parameter contains the Certification Authority ID, which identifies a certification authority's advertising system, such as the Trustworthy Accountability Group (TAG).
  • # display (optional comment) - Everything after the # symbol is a comment left by the publisher and have no value to the advertisers. They are entirely optional and may be left to assist in identifying the type of inventory sold to the indicated partner. Because this hashtag is a comment, it will not be picked up by the crawling script unless particular adjustments are made to it.

Why Should I Use Ads.txt As A Publisher?

As we mentioned before, the primary goal of ads.txt is to combat ad fraud—something that affects all publishers, big and small. By white-listing authorized sellers in your ads.txt file, you can take back control of your inventory and ensure that your ad space is only being sold through reputable companies.

Snigel has helped publishers get the most out of their inventory since 2011. With our cutting-edge programmatic advertising solution, AdEngine, publishers have seen an average revenue increase of 57%.

Get in touch to learn more about how Snigel can help you make the most out of your ad inventory and stay on top of industry updates.

About the Author

Ira is Snigel's Head Of Marketing. She supports our team and publishers by creating awesome guides on the latest adtech trends. Ira's background is in software development, communications, and media.

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