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By Aqilliz
Published on July 27, 2020
It’s no secret that ad fraud has been running rampant in the digital advertising industry for years.
If we rewind and go back in time, we’ll find ourselves in 2013—almost a decade ago when the digital advertising ecosystem was hardly reminiscent of the sophisticated landscape of tools and technologies that it is today. That year, cybersecurity firm White Ops found that 1 in 6 PCs were infected with bots and that 20 to 90 percent of all clicks on ads were fraudulent, leading to a US$6 billion dollar loss for the industry.
Has this changed? Not really. In fact, it’s only getting worse.
Just last year alone, it was found that an estimated $23 billion was lost to ad fraud globally. On top of that, advertisers and publishers are increasingly discontented with the lack of trust and transparency within the programmatic supply chain, as well as the amount of counterfeit inventory within the digital advertising ecosystem.
To combat this billion-dollar problem, the industry has put forward many solutions to better address this issue—with varying levels of success. In an effort to ensure accountability and legitimacy on both ends of the campaign supply chain, the Interactive Advertising Bureau (IAB) Tech Lab launched ads.txt and sellers.json as tools to clean up the online advertising supply chain and provide transparency in what is a highly opaque industry.
What are ads.txt and sellers.json and how do they work?
As the IAB Tech Lab explains: “Ads.txt stands for Authorised Digital Sellers and is a simple, flexible and secure method that publishers and distributors can use to publicly declare the companies they authorise to sell their digital inventory.” Basically, it’s a text file that site publishers can post to indicate the partner accounts that are authorised to sell their inventory. Programmatic platforms can also integrate ads.txt files to confirm which publishers’ inventory they are authorised to sell. In turn, this enables ad buyers to avoid sellers who misrepresent inventory, resell without permission, or spoof domains.
In a similar vein, sellers.json can be likened to the next step from ads.txt. While ads.txt allowed ad buyers to see what publishers and distributors have been authorised to sell their inventory, it only revealed one side of the coin. With sellers.json, ad buyers can see the other side as well—the sellers’ side. Like the SSP (supply-side platform) version of the ads.txt file, sellers.json documents the relationship between SSPs and their publishers. In the file, they’ll have to list all their authorised reseller partners, along with their seller ID and details of their legal entities. This gives publishers a clearer picture of who is paying or receiving money and allows ad buyers to make better informed decisions in the process.
As the digital landscape has grown in sophistication, additional measures have also come in place to protect new forms of media such as mobile in-app and OTT advertising. To that end, app-ads.txt was developed by the IAB Tech Lab in recognition of the growing rates of ad fraud across these mediums.
Ads.txt, app-ads.txt, and sellers.json all share the same goal—to provide information about buyers, sellers, and resellers, and how ad inventory is being sold.
Why does it matter?
Unauthorised reselling has been a major scourge in the programmatic advertising ecosystem, and unless buyers contacted publishers directly, they would have had no way to know which SSPs are authorised to sell a particular publisher’s inventory. By creating a depository of authorised sellers, buyers will be able to determine which programmatic firms have legitimate access to the inventory they seek.
Typically, ad tech vendors buying and selling impressions on the open exchange work with a vast array of intermediary resellers, all of which work with other resellers—this complex web of intermediaries involved in the sale of every impression makes it virtually impossible to keep track of who is reselling whose inventory, whether they are authorised to or not.
What are their benefits?
Over time, trust in the programmatic supply chain has been eroded due to transparency issues and the prevalence of fraud. Ads.txt serves to bring back a certain degree of transparency by making all this information publicly accessible and gives ad buyers greater confidence in knowing every single reseller involved in the process. Similarly, sellers.json can improve the supply-path optimisation (SPO), cutting questionable intermediaries and allowing ad buyers to optimise the path to the publisher’s inventory.
With a higher level of trust, ad buyers will get more value out of their marketing dollars and are more likely to increase their spending—it’s a win-win for both sides. On top of that, ads.txt and sellers.json are relatively simple to use and can be updated with minimal effort. Thanks to its accessible format, publishers and sellers don’t need a high degree of technical know-how in order to implement them.
What are the pitfalls?
In theory, ads.txt and sellers.json can be efficient tools for managing the relationships between publishers, advertisers, and brands in a transparent and secure way. While both are certainly useful additions to the programmatic industry to help combat the rise in fraudulent activity, the rate of adoption is still falling short. According to, only around 44 percent of the top 1,000 websites ranked by the analytics service Alexa Internet Inc. had implemented ads.txt. For ads.txt and sellers.json to be truly successful in providing end-to-end transparency, it is important that all publishers, SSPs and exchanges adopt these specifications.
In addition, relying on ads.txt and sellers.json data alone may not be enough to inform buyers’ decisions about which exchanges they ought to work with and which impressions should be paid for—other processes are needed to sniff out the bad actors and ensure that they get the most value for every media dollar spent. This means that intermediaries are still needed to provide additional assurances to maximise the benefits of these tools. This can take shape in the form of third-party verification firms or contacting suspicious vendors to ask for documentation to prove they have a relationship with the publisher for which they say they are selling ads.
Alternatively, emerging technologies such as blockchain can provide a promising solution to the industry’s transparency woes. With a distributed, immutable ledger that all campaign stakeholders are able to access with ease, brands and advertisers alike are able to ensure that all impressions being processed and paid for are valid. This process can be better automated via parameters that are hardcoded into smart contracts that can flag whether impressions are legitimate or not. With blockchain, advertisers stand to gain even greater visibility into who is taking a chunk out of their ad dollars before reaching publishers.
The introduction of tools such as ads.txt and sellers.json brought much-needed transparency and efficiency to the programmatic supply chain, and are positive signs that the ad tech industry is maturing. The fight against fraudulent activities in the online advertising ecosystem remains a continuing battle, and while it may not be the silver bullet, such efforts are vital to ensuring that the industry continues to progress into a model that promotes transparency and proactively takes action against ad fraud and other illegitimate practices.