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ads.txt and app-ads.txt Now Available for Connected TV and Over-the-Top Inventory

IAB Tech Lab Releases Standard to Reduce Fraud and Increase Transparency for CTV and OTT ad Inventory;
In Public Comment until January 14, 2021

New York, NY – December 15, 2020 – IAB Tech Lab has released the authorized digital sellers list (ads.txt) specification and its mobile app counterpart (app-ads.txt) to address transparency and anti-fraud for Connected TV (CTV) and Over-the-Top (OTT) inventory, for a 30-day public comment period, which begins today and lasts until January 14, 2021. 

Through these enhancements, the IAB Tech Lab Programmatic Supply Chain Working Group intends to support CTV / OTT apps in which multiple entities may have ownership rights over ad slots, commonly referred to as “inventory sharing.” In OTT, these situations often arise from relationships including virtual multichannel video programming distributors (vMVPDs), device/OS platforms, or as a result of various carriage agreements (TV Everywhere apps). The ads.txt and app-ads.txt specs have been updated to include the ability to designate another domain as a trusted partner, and validate the sellers upon a bid request from that partner.  An implementation guide has also been provided to clarify the use of this feature as well as various fields in OpenRTB (real-time bidding) that were being overloaded (i.e., used for purposes other than originally intended). 

“The Connected TV marketplace can be complex and requires a new approach to ads.txt to increase transparency among buyers and sellers,” said Amit Shetty, Sr. Director, Product, IAB Tech Lab. “As Connected TV growth continues to skyrocket, having standards that support these formats is critical.”

“ads.txt is an important update for buyers of Connected TV inventory, to ensure that the sector is armed with the tools to fight fraud and grow ad spend,” added Neal Richter, Chief Scientist, SpotX, and Chairperson, IAB Tech Lab Board. “We look forward to providing this standard that buyers have relied on when buying web and mobile digital inventory to Connected TV. This update will arm sellers with the ability to model the complex relationships in CTV needed to ensure that a seller and inventory are legitimate.”

“This new proposal for the app-ads.txt specification is a positive step forward for ad quality in TV streaming,” said Bill Simmons, VP Product Management, Roku. “Roku has consistently been at the forefront of making TV ad security and programmatic ad quality a top priority and has led the industry to adopt the highest standards protecting both content partners and marketers. We are very pleased to continue our commitment to ad quality and security today as the Roku Channel Store becomes the first TV streaming platform to standardize ads.txt support for the industry.”

Established in Spring 2017, ads.txt is a set of standards for publishers and distributors to declare who is authorized to sell their inventory, improving transparency for programmatic buyers. The app-ads.txt specification is an extension of the original ads.txt standard to meet the requirements for applications distributed through mobile app stores, connected television app stores, or other application distribution channels.  

To review the proposed standard and provide feedback, please go to:

About IAB Technology Laboratory 

Established in 2014, the IAB Technology Laboratory (Tech Lab) is a non-profit consortium that engages a member community globally to develop foundational technology and standards that enable growth and trust in the digital media ecosystem. Comprised of digital publishers, ad technology firms, agencies, marketers, and other member companies, IAB Tech Lab focuses on solutions for brand safety and ad fraud; identity, data, and consumer privacy; ad experiences and measurement; and programmatic effectiveness. Its work includes the OpenRTB real-time bidding protocol, ads.txt anti-fraud specification, Open Measurement SDK for viewability and verification, VAST video specification, and Project Rearc initiative for privacy-centric addressability. Board members/companies are listed at:

For more information, please visit:

Kate Tumino / Brittany Tibaldi
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