Ads.txt (Authorized Digital Sellers) is a simple text file that publishers place on their websites to declare which companies are authorized to sell their ad inventory. It's a public list that helps prevent ad fraud by giving buyers transparency into the supply chain.
Digital ad fraud costs advertisers billions each year. Fake domains and unauthorized resellers can trick ad buyers into paying for inventory that doesn't exist or appears on low-quality sites.
Ads.txt solves this problem by giving everyone a public source of truth. Buyers can quickly verify if a supply partner is approved by the publisher.
Every participating publisher hosts the file in the root directory of their website. View it by typing:
https://www.example.com/ads.txtFraudsters disguise low-quality sites as premium domains. Ads.txt blocks this because buyers can verify if the domain authorizes the seller.
Resellers buy cheap ad inventory and sell it at higher prices. Ads.txt discourages this by making the supply chain transparent.
Ads.txt is a text file that lists which companies are authorized to sell a publisher's ad inventory.
It's not mandatory, but most legitimate publishers use it to protect their reputation and maximize ad revenue.
Mobile apps use app-ads.txt, which serves the same purpose for in-app inventory.