Title: Understanding Ads.txt and App-Ads.txt in Programmatic Advertising
Introduction In the digital advertising ecosystem, transparency and fraud prevention are critical for ensuring advertisers purchase legitimate inventory. The ads.txt and app-ads.txt initiatives were developed by the Interactive Advertising Bureau (IAB) Tech Lab to enhance transparency and reduce fraud in programmatic advertising. As a leader in media technology, Amagi supports industry-wide adoption of these standards to create a more secure and trustworthy marketplace. This article provides an overview of ads.txt and app-ads.txt and their role in digital advertising.
What is Ads.txt and App-Ads.txt? Ads.txt (Authorized Digital Sellers) and app-ads.txt are publicly accessible text files that website and app owners use to declare authorized sellers of their digital ad inventory. These initiatives help prevent unauthorized reselling and misrepresented inventory, commonly associated with domain spoofing and arbitrage fraud.
- Ads.txt is used by websites to list authorized sellers of their inventory.
- App-Ads.txt is the mobile and connected TV (CTV) counterpart, designed for app-based advertising environments.
By implementing and maintaining these files, publishers and app developers provide advertisers with a way to verify legitimate inventory sources and prevent unauthorized intermediaries from selling fake impressions.
Why Ads.txt and App-Ads.txt Matter
- Prevents Domain Spoofing – Fraudsters can falsely represent premium publishers to deceive advertisers into buying fraudulent impressions. Ads.txt prevents such practices by ensuring only authorized sellers can transact inventory.
- Enhances Transparency – Advertisers can easily verify whether an ad exchange or supply-side platform (SSP) is an approved seller.
- Protects Publisher Revenue – Publishers and app owners can ensure ad revenue is not diverted to fraudulent intermediaries.
- Supports Industry Standards – These initiatives align with IAB standards and are widely adopted by premium advertisers and platforms.
How Ads.txt and App-Ads.txt Work Publishers and app owners must create and host a plain text file (ads.txt for websites, app-ads.txt for apps) on their domains. This file includes a list of authorized sellers, specifying:
- Ad System (SSP or Exchange Name) – The platform authorized to sell the inventory.
- Seller Account ID – The unique account ID associated with the publisher.
- Relationship Type – Either ‘DIRECT’ (publisher has a direct relationship with the seller) or ‘RESELLER’ (seller is authorized to resell inventory).
- Certification Authority ID – Optional field that references a certification body for further verification.
For app-ads.txt, the file must be placed in the developer’s official domain, which is referenced in the app store listing to allow buyers to verify its authenticity.
For additional documentation for Platforms, continue here.
For additional documentation for Content Owners, continue here.
Implementation Best Practices
- Regularly update and audit the ads.txt and app-ads.txt files to ensure they reflect current authorized sellers.
- Work only with verified SSPs and ad exchanges that adhere to transparency and fraud prevention standards.
- Ensure correct placement of files on publisher domains and app store-listed developer sites.
Amagi’s Commitment to Ads.txt and App-Ads.txt Compliance At Amagi, we advocate for the adoption of ads.txt and app-ads.txt to create a more secure and fraud-free ad marketplace. We work with content partners and advertisers to ensure proper implementation, helping reduce invalid traffic and improve ad spend efficiency.
Conclusion Ads.txt and app-ads.txt are essential tools in combating ad fraud and ensuring transparency in the programmatic supply chain. By implementing these industry standards, publishers and app developers can protect their inventory, maintain revenue integrity, and foster trust with advertisers.