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Combating Ad Fraud with IAB’s ads.txt Initiative

Post on November 15, 2017 by Vin Diec

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Vin Diec VP, Sales Operations & Inventory Quality

In a recent blog post about inventory quality, I discussed how PubMatic is fighting the good fight. We routinely perform brand-safety checks and inventory screening across multiple formats and platforms.

Additionally, we announced our Fraud-Free Program with a money-back guarantee for demand partners. If fraud is detected on PubMatic’s platform, our demand partners won’t have to pay for it provided that certain criteria are met. At PubMatic, we have made a commitment to take on ad fraudsters and prevent them from benefitting from the hard work of legitimate publishers and resellers.

So, in the spirit of our continued efforts to clean up the online advertising ecosystem, we are reiterating our support of the IAB’s ads.txt initiative.

ads.txt and ad fraud

ads.txt is an initiative by the IAB Tech Lab designed to fight inventory fraud. The ‘ads’ part of ads.txt actually stands for Authorized Digital Sellers. It is a very simple method for publishers to identify and broadcast all the companies in the programmatic ecosystem who are authorized to sell their digital inventory.

The initiative is designed to stop domain spoofing, which is a massive problem in the programmatic ecosystem. An example of domain spoofing is when a seller indicates it is selling “” inventory but the ad actually runs on ““ Advertisers think they’re getting premium inventory but their ad actually runs on a useless site.

Meanwhile, legitimate publishers miss out on ad dollars meant for them. ads.txt allows buyers to quickly check that the company they’re buying the inventory from is authorized to resell that inventory. The ads.txt files are placed on the domain’s secure server, so there’s no opportunity for the file to be spoofed.

Limitations of ads.txt

At this time, ads.txt still has a few limitations.

First, it does not cover mobile app inventory. Second, there’s no indication of ad format in the spec so an authorized reseller of display advertising may also be an unauthorized reseller of video ads. But, they still show up in ads.txt files as an authorized reseller of the publisher’s inventory. There’s also social engineering going on where resellers are trying to finagle their way onto ads.txt files. Finally, there is the risk of basic human-error, particularly with spelling errors, leading to drop-offs of legitimate inventory sellers.

Still, the future looks bright with buyers like Google, The Trade Desk, and MediaMath having announced their intentions to read the ads.txt signal when buying inventory. We expect most buyers will follow suit.

What’s next?

We have aggressively pushed our inventory suppliers to adopt ads.txt as the benefits are clear.

According to Digiday, at the beginning of September 2017, only 12 percent of the top ten thousand publishers had ads.txt files. By the end of October, that number had risen to 44 percent. It’s an impressive gain, but there’s still work to be done.

While an ads.txt file is very easy to create and maintain, many publishers still have not devoted the resources to understanding and implementing ads.txt. This is simply because they haven’t needed to do so up to now.

However, as leaders in the industry like PubMatic, require the adoption of ads.txt, we expect this number to snowball into 2018. The growth will be organic as the initiative gains momentum and buyers use ads.txt to determine whether to buy inventory or not.

Join us

PubMatic has been a strong proponent of the ads.txt initiative from the start, as a founding member of the IAB Tech Lab. We recognize the value of its adoption across sellers and publishers in pursuing our goal of a fraud-free platform and ecosystem. To that end, we’ve set a goal of full adoption of ads.txt across our platform by the end of Q1 2018. Stay tuned and let us know how we can partner with you.