More Transparency in CTV through Ads.txt and App-ads.txt

Over the last several years, the programmatic industry has adopted the IAB Tech Lab’s Authorized Digital Sellers (ads.txt and app-ads.txt) standards to provide transparency into the supply chain, help prevent domain spoofing, and disallow unauthorized reselling of inventory across web and mobile app. These specifications allow marketers to confidently buy supply through authorized selling channels, while ensuring media owners can preserve the value of their inventory.

With the connected TV (CTV) ad market expected to reach $29.5 billion by 2024, it’s time to adopt this same level of transparency across CTV supply. Bringing clarity to the complex and fragmented CTV supply chain allows media buyers to transact safely while building trust among all participants in an emerging market.

As part of our unwavering commitment to exchange quality, we’ve updated our compliance policies to only sell inventory when Index Exchange authorization has been correctly implemented in ads.txt and app-ads.txt for web, mobile app, and CTV inventory. Additionally, we now require CTV publishers and platforms to adopt the IAB Tech Lab’s guidance on ads.txt and app-ads.txt for CTV to transparently declare inventory sharing agreements, which are common in CTV. 

These updates will help propel transparency in CTV and ensure that media owners are well prepared to meet the growing expectations of DSPs to support these standards. Here’s what you need to know about adopting and implementing the latest version of ads.txt and app-ads.txt for CTV.

Why are ads.txt and app-ads.txt increasingly important for CTV publishers and platforms?

Media owners lose out on revenue any time an ads.txt entry is missing, incorrectly implemented, or the file is unreachable as buyers undervalue unauthorized supply and choose not to bid.

This has been apparent for some time in web and mobile app environments, where ads.txt and app-ads.txt are already widely adopted. As DSPs have updated their policies to buy only supply where they can authorize the seller via ads.txt or app-ads.txt, we’ve seen that authorized supply transacts at six times the revenue per mille (RPM) of unauthorized supply in web environments on our platform, and five times as high in mobile app.

This same effect is taking hold in CTV as marketers increase spend and DSPs implement similar policies as they have for web and mobile app. We’ve seen authorized supply in CTV garner over two times the RPM of similar unauthorized supply. 

It’s clear that driving adoption of these standards in CTV is increasingly prudent for media owners to maximize the value of their inventory. However, the underlying commercial and technology frameworks in CTV create complex supply paths for media owners to distribute inventory. Adoption has lagged because the original specifications couldn’t account for CTV’s unique monetization relationships. 

To handle these complexities, the IAB Tech Lab released enhanced versions of ads.txt and app-ads.txt designed specifically for CTV.

How do ads.txt and app-ads.txt work in CTV?

In the simplest use cases, a media owner hosts an ads.txt or app-ads.txt file that lists the parties authorized to sell its inventory. When inventory is auctioned, each participant in the auction chain can verify the authorization of the seller in the bid request using the information in ads.txt or app-ads.txt file, as shown below. 

However, CTV often becomes more complicated with the prevalence of inventory-sharing agreements, where multiple parties have authorized ad rights. For instance, a content owner who has the right to sell ads on their content may allocate a portion of ad supply to a CTV app owner in return for distributing the content to viewers. Ads will be shown through the distributor’s app, which is represented in the bid request. 

In these agreements, both the content owner and the app owner, or distributor, are direct sellers (and final payees) of the portion of supply they have rights to. Previously, buyers couldn’t verify the content owner’s ads.txt file and authorized sellers solely by looking at the app bundle represented in the bid request. This means buyers couldn’t verify authorization for these opportunities as they couldn’t cleanly delineate content owners as direct supply paths.

To support these relationships, the IAB Tech Lab introduced the inventorypartnerdomain variable to both ads.txt and app-ads.txt files and as an extension in OpenRTB bid requests. 

The new variable allows both content owners and CTV distributor apps to provide transparency into authorized sellers. When distributors sell inventory through their apps, they need only follow the standard requirements for app-ads.txt. In the case of shared inventory agreements with content owners, distributors will need to identify the content owner by denoting them as an inventory partner in their app-ads.txt file, as seen below. They’ll also need to declare the content owner as the inventorypartnerdomain in the bid request.

A look ahead at programmatic transparency

As emerging inventory channels like CTV continue to attract larger budgets and high CPMs, the expectations for transparency will increase. Marketers will continue shifting budgets towards trusted and clear supply channels where they can trust the app from where supply originates and content the ad appears with, as well as verify all the participants involved in a transaction. 

Ensuring supply meets industry expectations for correctly implemented ads.txt, app-ads.txt, and sellers.json standards is becoming table stakes to participate in the programmatic CTV market. Future iterations of the current industry standards, including ads.txt 1.1 and OpenRTB 2.6, will keep supply safe, transparent, and valuable as the industry evolves. And Index will be there to guide you each step of the way.

Visit our Knowledge Base to review ads.txt and app-ads.txt implementation requirements, or contact our team for additional adoption guidance.

Jeremy Grant

Jeremy Grant

Senior product manager

As the senior product manager for exchange quality, Jeremy Grant leads Index Exchange’s product efforts to operate a high-quality marketplace for both media owners and marketers. During his eight-year tenure at Index, Jeremy has held leadership roles across the analytics and service teams. He currently serves on the IAB Tech Lab’s Programmatic Supply Chain working group supporting efforts for ads.txt, app-ads.txt, and sellers.json. Prior to Index, Jeremy worked in finance as an analyst at a boutique investment fund.

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