After a slowish start, App.ads.txt adoption is surging, but there’s still an enormous longtail of apps that shrug their collective shoulders at the industry spec designed to cut down on app ad fraud.
App-ads.txt is an IAB Tech Lab initiative that involves app publishers providing text files listing the ad networks and other sources that are authorized to sell their inventory. It’s basically the app version of Ads.txt.
Fraud detection company Pixalate, which tracks Ads.txt and App-ads.txt compliance, found that use of App-ads.txt increased 177% between Q1 and Q2 and then hockeysticked 1,222% percent between the second quarter and now.
Overall, more than 7,000 iOS apps and over 46,000 apps in Google Play have made the move to place an App-ads.txt file, according to the IAB Tech Lab.
However, it’s clear that most apps aren’t embracing the spec, considering there are over 2 million apps apiece in the App Store and Google Play.
Focusing on the bigger fish
Just looking at the number of apps that haven’t adopted App-ads.txt doesn’t tell the full story.
For one, not all apps monetize through advertising, said Ian Trider, director of RTB platform operations at Centro. Second, he said, a relatively small number of apps are responsible for the majority of available inventory, and among these apps, there’s a much higher participation rate.
The goal is to protect the largest possible percentage of overall ad impressions in the programmatic ecosystem, rather than wooing myriad longtail apps to adopt the standard, said Sam Tingleff, CTO of the IAB Tech Lab.
“The question is, are the highest-scale apps protected and is the vast majority of impressions protected?” Tingleff said. “We’re already reaching the point at which DSPs cannot ignore this.”
Buyers and sellers unite
Demand-side platforms and exchanges, including Centro, Google’s DV360, The Trade Desk and AppNexus are beginning to enforce App-ads.txt, and sell-side players are cautioning their publishers that ignoring the spec could result in a revenue hit.
“Developers need to feel the pinch of reduced spend due to not having an App-Ads.txt file in place,” said Eric Bozinny, director of inventory quality at PubMatic, which is seeing buyers start pushing dollars toward authorized inventory.
Sixty-one percent of app spend goes to authorized apps selling through PubMatic, but only 24% of apps that monetize with advertising are authorized, which means developers that choose to adopt App-ads.txt files have an advantage during the transition.
In early September, Twitter-owned mobile ad exchange MoPub sent an email to its developer base with the subject line “[Action Needed] Implement APP-ADS.TXT.” The message warned app publishers that DSPs are starting to “build targeting capabilities specifically intended to target away from any supply source that does not list MoPub as an authorized direct seller within App-ads.txt.”
The DSPs getting serious about applying the standard should spur even more adoption, said Lisandro Lejano, a senior product manager at MoPub.
“At first, publishers were [taking] a wait-and-see approach,” he said. “They were waiting for DSPs to start enforcing.”
And now that they are, pubs are hopping to. As of mid-September, publisher adoption of App-ads.txt on MoPub’s platform was at 40% among its top apps, while Centro says that 70% of the traffic it’s seeing comes from publishers with App-ads.txt files.
Not a panacea
The App-ads.txt initiative has so far revealed where resellers are arbitraging inventory, said PubMatic’s Bozinny. The file acts as a signal of quality, he said, and provides a way to determine whether a reseller is authorized to sell inventory.
But if an app chooses not to publish a file, there’s still no easy way of knowing if a reseller is authorized to sell, Bozinny said.
And App-ads.txt is vulnerable to spoofing, just like its desktop sibling, Ads.txt. Simply checking to see if a file exists isn’t the same as checking its contents, because bad actors can fake an App-ads.txt file to make it look like their app is working with big exchanges.
Most people claim to check Ads.txt or App.ads.txt files, but the question is how thorough they are, said independent fraud researcher Augustine Fou.
“Was all or part of it plagiarized? Did you cross-reference every domain and seller ID on a non-sampled basis? Were those details provided to the client for independent verification?” Fou said. “If not, then don’t claim you fought fraud because you have App-ads.txt.”