Authorized Digital Sellers

What is Authorized Digital Sellers?

Authorized Digital Sellers is the IAB Tech Lab initiative that gives ads.txt its name, letting publishers and app developers publicly declare who may sell their ad inventory, and working alongside sellers.json and the SupplyChain object.

Also known as: ads.txt initiative

How it works

What does the family include?

Think of it as one initiative with several parts, each covering a different environment or question.

• ads.txt is the original file for websites. A publisher posts it at the root of its domain, listing each authorized advertising system, account ID and relationship (DIRECT or RESELLER).
• app-ads.txt extends the same idea to apps. The IAB Tech Lab describes it as covering apps distributed through app stores, connected TV app stores and other distribution channels (IAB Tech Lab). Because apps have no website of their own, the developer posts the file on the developer website listed in the app store, and verifiers find it by reading the store listing (app-ads.txt specification).

Two companion standards complete the picture. sellers.json is published by each advertising system and reveals who sits behind the account IDs that ads.txt lists (IAB Tech Lab). The SupplyChain object travels inside each bid request and records every party that handled that impression (SupplyChain object specification).

How do the pieces work together?

Each standard answers one question. ads.txt and app-ads.txt answer "who is allowed to sell this inventory?" sellers.json answers "who is this seller account?" The SupplyChain object answers "who touched this particular impression?" A buyer that checks all three can confirm that every hop was authorized and identified, which is the basis of much supply path optimization.

Why it matters

What problem does it solve?

Programmatic advertising made it easy for anyone to send a bid request that claims to come from a well-known site. Without a way to check, a buyer could pay for what it thought was premium inventory and get something else entirely. The IAB Tech Lab's answer was a public, publisher-controlled record of who is authorized to sell each property. Its ads.txt page describes the goal as increasing transparency so buyers can verify inventory and bad actors find it harder to sell counterfeit supply (IAB Tech Lab). The name "ads.txt" is simply short for Authorized Digital Sellers.

What it means for buyers and sellers

For buyers, it is a practical defence against spoofed and resold inventory they did not intend to buy. For publishers and app developers, being correctly listed is close to a requirement, because many buyers will not bid on paths they cannot verify. It does not catch every problem: bots and other invalid traffic need separate measurement.

Example

IncrementX perspective

Representation across web, app and CTV means the authorization trail has to be right in every environment, not just on the main website. Good media representation includes making sure the publisher's ads.txt and app-ads.txt records match the partners actually selling its inventory.