ads.txt – Authorized Digital Sellers

IAB Tech Lab’s ads.txt Specification version 1.0.1 is currently implemented in the digital ad industry to fight against fraud and misrepresented domains. Click the button below to view the spec.

IAB Tech Lab released “Authorized Sellers for Apps (app-ads.txt) Beta 1.0,” for public comment as the next step to fight inventory fraud for apps. 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.  This addresses the market’s need for ads.txt functionality for mobile apps. Public comment is open for 60 days, closing on February 4, 2019. Published as a beta draft, the OpenRTB working group welcomes some early adoption of the app-ads.txt specification through the process of finalisation.

The working group is expecting to exit beta after the 60 day public comment period, taking public comment/feedback within this time. There is no set date for when app-ads.txt will be out of beta, and anyone interested can join the OpenRTB working group to engage with this initiative.

Any comments or questions can be directed to and will be distributed to the working group for review.



Are you buying authorized inventory? Are you looking for an efficient way to access ads.txt file contents?

IAB Tech Lab offers “ads.txt aggregator” – a critical tool to support its ads.txt anti-fraud initiative. This service provides regular updates on publishers’ approved ad sellers, making it easier for marketers, agencies, and platforms to eliminate fraudulent inventory sources, and fight against domain misrepresentation. This tool provides subscribers with access to structured aggregate data files.

Engineers – are you building a crawler to find ads.txt files? View an open source crawler for ads.txt. This prototype example crawler is given a list of URLs or domains etc and saves them to a SQLite DB table. Please note, this is only an example prototype crawler and would be suitable for a very modest production usage – read more on the github repository.

Open source prototype crawler

As part of a broader effort to eliminate the ability to profit from counterfeit inventory in the open digital advertising ecosystem, ads.txt provides a mechanism to enable content owners to declare who is authorized to sell their inventory.

Previous Version: ads.txt Spec Version 1.0 | Blogpost

What is the ads.txt project?

The mission of the ads.txt project is simple: Increase transparency in the programmatic advertising ecosystem. ads.txt stands for Authorized Digital Sellers and is a simple, flexible and secure method that publishers and distributors can use to publicly declare the companies they authorize to sell their digital inventory.

By creating a public record of Authorized Digital Sellers, ads.txt will create greater transparency in the inventory supply chain, and give publishers control over their inventory in the market, making it harder for bad actors to profit from selling counterfeit inventory across the ecosystem. As publishers adopt ads.txt, buyers will be able to more easily identify the Authorized Digital Sellers for a participating publisher, allowing brands to have confidence they are buying authentic publisher inventory.

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The IAB Tech Lab OpenRTB Working Group has developed the ads.txt spec. Questions can be sent to

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