Ads.txt
An IAB standard that publishers use to declare which companies are authorized to sell their ad inventory, combating unauthorized reselling.
What Ads.txt means
Ads.txt (Authorized Digital Sellers) is an IAB Tech Lab standard that allows publishers to publicly list the companies authorized to sell their digital advertising inventory. The ads.txt file, hosted on the publisher's root domain, contains a list of authorized sellers with their platform IDs. This standard was created to combat domain spoofing and unauthorized inventory reselling in programmatic advertising. For advertisers, buying from ads.txt-verified sources reduces the risk of ad fraud, ensures budget goes to legitimate publishers, and improves supply chain transparency. Most major platforms and DSPs support ads.txt filtering. The related app-ads.txt standard serves the same purpose for mobile app inventory. Compliance benefits include reduced fraud exposure, better brand safety, and alignment with industry transparency standards.
Related terms
Programmatic Advertising
Automated buying and selling of digital advertising through real-time auctions and algorithmic decision-making.
Ad Fraud
Fraudulent activity that manipulates ad delivery, clicks, or conversions to generate illegitimate revenue or inflate metrics.
Brand Safety
Measures taken to ensure ads do not appear alongside harmful, offensive, or inappropriate content that could damage brand reputation.
Supply Path Optimization
The practice of evaluating and selecting the most efficient, transparent, and brand-safe paths to purchase ad inventory.