So what is ads.txt?
It is an IAB-approved text file that aims to prevent unauthorized inventory sales.
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.
How does it work?
- A publisher publicly lists the Exchanges, and account IDs that are approved to sell their ad-space in a file called Ads.txt on their domain.
- DSPs crawl the domains they’ve previously served impressions on looking for this /ads.txt.
- When a standard OpenRTB BidRequest is made from an Exchange to the DSP, it checks the declared Domain and Publisher ID against the ads.txt previously crawled from that domain.
- No match — no Bid.
- If no ads.txt is present, it’s considered open for any Exchange to sell.
Publishers drop a text file on their web servers that lists all the companies that are authorized to sell the publishers’ inventory. Similarly, programmatic platforms also integrate ads.txt files to confirm which publishers’ inventory they are authorized to sell. This allows buyers to check the validity of the inventory they purchase.
How can buyers use ads.txt to check who is authorized to sell?
If an exchange and the pubs it represents each adopt ads.txt, bidders can check their tags for the presence of an ads.txt file to verify that the exchange and publisher have a legitimate connection to each other.
Are there any other ways to check which sellers are authorized using ads.txt?
Yes. Let’s say a buyer bought HuffPost inventory but was skeptical of the exchange the inventory came from. If HuffPost used ads.txt, the buyer could head to huffpost.com/ads.txt to see if the exchange is listed as an authorized seller of HuffPost inventory.
Why does this matter?
Unauthorized reselling is a major scourge in programmatic advertising, and unless buyers contacted publishers directly, they’ve had no way to know which SSPs are authorized to sell a particular publisher’s inventory, Sullivan said. Creating a depository of authorized sellers should help buyers determine which programmatic firms have legitimate access to the inventory they seek.
What is a ‘Direct’ seller and a ‘Reseller’?
“Direct” means that the SSP or exchange has a direct business relationship with the publisher to sell the publisher’s inventory.
“Reseller” means the publisher has authorized another company to resell inventory on the publisher’s behalf.
What does an ads.txt file look like?
It’s a standard CSV format, which could either be dynamically generated or simply a file, just named ads.txt. Publishers should host the “/ads.txt” file on their root domain and not on subdomains.
Check out a live example: http://uk.businessinsider.com/ads.txt
Ads.cert is the Interactive Advertising Bureau’s upgrade to ads.txt and uses cryptographically signed bid requests to show the path of inventory and authenticate that inventory.
So what is ads.cert, and how is it different from ads.txt?
As mentioned earlier, Ads.txt verifies that a business is authorized to sell a publisher’s inventory, giving the publisher more control and assuring buyers they’re only buying from authorized sellers.
Ads.cert goes a step further and validates the information that passes between buyer and seller at each stage of the digital ad supply chain, ensuring it’s not vulnerable to being modified or gamed. It’s like a digital signature that lets buyers verify a specific site’s inventory, and it stops fraudsters from tampering with the inventory.
What kind of information is validated?
In the open exchange, buyers use data like domain, location, IP address, device, position on page, impression type and other variables to inform the value of the impression. These variables can be manipulated to look like more valuable impressions. Ads.cert is intended to block that.
It’s one more step toward full transparency in digital ad transactions, which is what everyone in the supply chain (aside from fraudsters and shady vendors) is gunning for. It also means that a buyer can know for sure they’re not buying display inventory that’s been repackaged as video, for example.
Sounds good, is it live?
Not so fast. Ads.cert can only be implemented if a company has upgraded its tech infrastructure from OpenRTB 2.5 to version 3.0, which was released by the IAB and designed to handle new kinds of programmatic buying and selling such as header bidding, content sales, product recommendations and connected TVs.
How will it work on Mobile (i.e. in-app)?
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.
Steps to follow
1) Discover relevant inventory
2) Crawl app store
3) Crawl app-ads.txt file
How to get started with app-ads.txt?
If not done already, app publisher should make sure that the “developer website” field is up to date in the stores hosting the apps. Such websites will be used by the advertising systems to retrieve the app-ads.txt file.
The app publisher should upload a file named “app-ads.txt” into such website (please see the spec for full detail re location of the app-ads.txt file), with the list of authorized sellers of their app’s ad inventory per the official guidance. The content of the app-ads.txt file follows the same rules.