A new tool lets anyone search massive ad tech datasets. DecryptAds reveals which brokers operate on specific sites and apps. Researchers can now trace how location data is shared and sold.
For publishers, editors, and anyone managing digital content, understanding how advertising networks handle user data is critical for both compliance and audience trust. Investigating the ad tech ecosystem, however, has long been a challenge due to fragmented and obscure data sources. DecryptAds, a new research platform, aims to change that by aggregating and making searchable a vast trove of advertising industry files.
DecryptAds compiles ads.txt, app-ads.txt, and sellers.json files from across the web, allowing users to see which advertising brokers are active on a given website or app-and where else those brokers operate. This approach streamlines what was previously a labor-intensive process, enabling faster and broader analysis of data sharing practices in programmatic advertising.
Zach Edwards, chief product and research at DecryptAds, said the tool was built to help anyone quickly assess the data sharing implications of working with specific ad tech companies and data brokers. He noted that the platform is designed to empower researchers, journalists, and publishers to better understand the risks associated with programmatic advertising, especially when it comes to sensitive data like user location.
Real-time bidding (RTB) is a core mechanism in digital advertising, where companies compete to place ads in front of targeted users. This process can result in the collection of detailed device and location data, which sometimes ends up being sold to third parties, including government agencies. Past investigations, including those by 404media, have revealed how thousands of apps and websites leak location data through these channels.
Traditionally, uncovering these practices required leaks, insider sources, or technical analysis of individual apps. DecryptAds takes a different route by aggregating public files that list which ad systems are integrated into sites and apps, and which companies exchanges work with. The platform's database, as of this writing, includes over 284 million ads.txt files, nearly 184 million app-ads.txt files, and more than 201 million sellers.json files.
Users can search DecryptAds by app, advertising company, domain, or IP address. The tool also tracks changes in sellers.json files, which may help identify publishers or app makers who are quietly banned from multiple exchanges. Edwards said this monitoring could surface suspicious activity that would otherwise go unnoticed.
DecryptAds adds context to its data by assigning a "geo risk" score to ad systems. This score flags companies linked to sanctioned countries, U.S. adversaries, or financial secrecy havens. While a flag does not prove wrongdoing, it provides leads for further investigation. Edwards explained that companies with ties to Russia, China, or jurisdictions known for shell companies may warrant closer scrutiny, especially regarding data security and potential malvertising risks.
Security incidents in the ad tech ecosystem are not hypothetical. Last month, Adform, a major advertising company, reported that hackers had compromised its systems to replace cryptocurrency wallet addresses in users' browsers. DecryptAds data showed that nearly 20,000 websites, including 404media, listed Adform in their ads.txt or app-ads.txt files. After learning of the breach, 404media removed Adform from its ads.txt file.
DecryptAds' stated goal is to provide more transparency in programmatic advertising, helping publishers, security teams, and ad tech companies understand the risks of working with certain partners. By layering context onto the raw data, the platform aims to reduce exposure to unscrupulous publishers and improve privacy and security outcomes for everyone involved.
For those interested in the intersection of advertising and AI, a related analysis on how marketers are approaching ChatGPT ads can be found in this recent report.
DecryptAds is positioned as a resource for anyone seeking to navigate the complex web of data brokers and ad tech intermediaries. Its searchable database and contextual tools offer a new level of visibility into how user data is shared, sold, and potentially exposed across the digital advertising landscape.
