As of March 2019, a minor version update to the IAB Tech Lab’s ads.txt specification version 1.0.2 is available for industry adoption. Ads.txt specifies a mechanism for publishers to list their authorized digital sellers, in order to fight against fraud and misrepresented domains. Version 1.0.2 now details how publishers can indicate if they do not authorize any sellers. Click below to view the spec and implement now. View FAQ for ads.txt and app-ads.txt.
IAB Tech Lab released app-ads.txt version 1.0 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. The app-ads.txt final version 1.0 is now available for industry adoption.
- App developers: Read more about how you can implement ads.txt
- Buyers: Read more about targeting app-ads.txt inventory
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.
Additionally, a reference implementation of app store HTML parsing and app-ads.txt developer URL canonicalization libraries can be found here:
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.
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.
The IAB Tech Lab OpenRTB Working Group has developed the ads.txt spec. Questions can be sent to OpenRTB@iabtechlab.com
- View the Partner Interaction Guide
- Open Source implementation of a reference crawler written in Python
For more information:
- Read our press release on the ads.txt aggregator
- Read our press release
- Blog post: Helping the industry prevent the sale of counterfeit inventory with ads.txt
- View a webinar presentation with FAQ discussion
- View slides from ads.txt informational presentations
Were you looking for information on sellers.json? Click here to learn more about sellers.json and the OpenRTB SupplyChain Object