Understanding ads.txt and app-ads.txt

Purpose

This document explains the role of ads.txt and app-ads.txt as foundational mechanisms for publisher authorization and supply path transparency.

Key Takeaways

• ads.txt is a file published by web publishers to disclose authorized sellers.
• app-ads.txt extends the same idea to apps and CTV app environments.
• These standards improve selling transparency and help reduce seller spoofing, but they do not replace onboarding, placement registration, or broader trust controls.

Concept Flow

Draft Structure

1. What is ads.txt

• A public file hosted on a publisher domain.
• It declares which sellers are authorized to sell that publisher's inventory.

2. What is app-ads.txt

• The app counterpart to ads.txt.
• It links store metadata and developer domains to seller authorization.

3. Why it matters

• It helps reduce inventory spoofing and seller impersonation.
• It forms a baseline layer for supply path transparency.

4. Limitations

• It does not solve every fraud, quality, or trust issue on its own.
• Additional signals such as sellers.json, schain, and log validation are still important.

Prerequisite Document

• Publisher Onboarding and Placement Registration

Next Document

• Understanding sellers.json and schain