Overview

The Interactive Advertising Bureau (IAB) developed ads.txt to combat fraud in digital advertising, especially domain spoofing. Domain spoofing occurs when fraudulent publishers falsely claim to represent a legitimate website during real-time bidding (RTB), deceiving advertisers into buying fraudulent inventory. Ads.txt improves transparency and security by allowing publishers to publicly list the companies authorized to sell their ad space via txt file. This helps buyers verify legitimate inventory and avoid fraud by defining parameters in targeting. The system works across multiple platforms, including desktop sites, mobile websites, and mobile apps. By supporting ads.txt and app-ads.txt, advertisers can safely target verified inventory.

How it Works

For websites (ads.txt):

1. Website owners create an ads.txt file.
2. Site owner hosts this file at the root domain of their website (e.g.,  https://www.example.com/ads.txt).
3. The ads.txt file contains:
   • List of authorized supply-side platforms (SSPs).
   • Associated publisher IDs for each SSP, including authorization type (Direct or Reseller) to sell ad inventory for that specific website.

For mobile apps (app-ads.txt):

1. App developers create an app-ads.txt file.
2. App owner hosts this file on the root domain of the official developer website (not within the app itself).
3. The app-ads.txt file contains:
   • List of authorized supply-side platforms (SSPs).
   • Associated publisher IDs for each SSP, including authorization type (Direct or Reseller) to sell ad inventory for the developer's mobile apps.

Ads.txt Status Codes

Status codes are used in both filtering incoming ad requests and targeting specific types of inventory in ad platforms. They allow advertisers to make informed decisions about which inventory to bid on, enhancing transparency and trust in the digital advertising ecosystem. It's worth noting that while Ads.txt was is focused on web-based advertising, app-ads.txt is developed for mobile app environments. The principles remain similar, but instead of using website domains, app-ads.txt uses app bundle IDs to verify authorization.

INCLUDE or EXCLUDE logic can be applied to any of the following ads.txt statuses below in both inventory targeting of a line item and QPS filtering.