Let’s rewind: What is Ads.txt?



Let’s rewind: What is Ads.txt?

What is Ads.txt?


Let's take it from the top: What is ads.txt

Did you know that back in the day (circa 2017), there was virtually no safeguard in place for ad tech vendors to represent to their advertisers that they had access to your site’s ad space inventory?

 It was the ad-tech equivalent to the wild wild west. Anyone could fraudulently access your ad inventory through back doors and arbitrage tactics which diluted the ad dollars that came from advertisers into publisher’s bank accounts. 

This is why ads.txt was implemented across the open web, to ensure that only authorized buyers and sellers could transact on your ad inventory with your explicit permission.

So what exactly is Ads.txt though?

Ads.txt file is a simple text file that you add to the root domain of your website which is used as a record to show who can access your ad spaces and what relationship you have to that advertiser. 

Implementing ads.txt means you are allowing authorized groups to allocate and represent your ad inventory. A simple way to see your (or anyone’s for that matter) ads.txt file is to type “(Insert the URLhere)______.com/ads.txt” into the address bar, and something like the picture below will show up.

Ads.txt web file

This file is an itemized list of the advertising companies and the corresponding IDs that can transact on any ad on your URL. Its inception was intended to be the solution for digital advertising, bringing transparency to the industry where fraud was consistently happening. Ads.txt improved the marketplace, though it was not the end-all solution many hoped it to be.

On each line of your ads.txt, you’ll find the relationships of your inventory.

A DIRECT relationship suggests that the publisher works directly with that AdTech vendor. A RESELLER relationship means that the publisher authorized that vendor to sell the inventory. 

Just after a few months of adopting ads.txt, the industry saw many of the simple practices of ad arbitrage (where a middleman would collect inventory, package it, then resell it) fall apart. Some agencies completely disappeared once Ads.txt was adopted more widely. 

So that brings us to 2023 and the adoption of Ads.txt 1.1! 

Let us fill you in on what is happening now.

What’s New with Ads.txt 1.1

This new file version further clarifies the relationships of the supply path that publishers, providers, and buyers have. It was created so that the publisher’s inventory has a level of authority and transparency to make it more difficult for fraud to happen. 

Ads.txt 1.1 introduced three new values, OWNERDOMAIN, MANAGERDOMAIN, and CONTACT. The OWNERDOMAIN is the domain name of the company that owns the inventory, whereas MANAGERDOMAIN is the company that manages that inventory for the owner of that domain. CONTACT is the email address best used to contact someone in case of an error or opportunity.

Updated Ads.txt

If you’re a publisher, this is music to your ears. Adding another level of security is essential to ensure that your site’s ad space is sold only through authorized inventory sources. It’s the next step in letting the wild wild west stay in the past.

What’s New with Ads.txt 1.1

 Ads.cert is an upcoming authentication protocol, and its primary purpose is to take all the updates, such as ads.txt 1.1, and ensure they’re executed properly. Just like Ads.txt, it depends on public adoption to work optimally.  Mark Stenberg with Adweek said it best, 

“For the system to work, all parties involved in the programmatic supply chain must maintain the documents, which enable anyone to crossreference the lists of any two partners to confirm that they are licensed to work with one another.” 

Monumetric believes in not only improving the lives of our creators but also the industry in which we operate. We’ve implemented Ads.txt 1.1 across all of our publishers automatically. We’re confident that everyone wins when we advocate and implement security and transparency across every transaction touchpoint.


If you have more questions about Ads.txt, Ads.cert, or how to implement them on your site, please visit our Ads.txt blog post or reach out to our support team at support@monumetric.com

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