Sellers.json vs Ads.txt | Everything Publishers Should Know

IAB Tech Lab has already introduced ads.txt, sellers.json files, and the OpenRTB Supply Chain Object to prevent ad fraud. Statista predicts that by 2022 ad fraud costs will reach 44 billion U.S. dollars. The impact of ad fraud affects both sides–publishers and advertisers. Publishers can see the reduction in CPMs, poor quality of ads, and, most importantly, a negative impact on user experience.

In this article, you will learn about the sellers.json file, the differences between ads.txt and sellers.json. The next step will be to understand how OpenRTB supply chain object is going to affect you as a publisher and how it’s related to sellers.json file.

Before we dig into more detail, let us remind you about ads.txt.

Ads.txt Description

The main goal for ads.txt file is to take care of publishers’ ad inventory to avoid ad fraud. This file gives more control for you as a publisher to see if sellers are authorized to sell your ad inventory. We covered all the essential details about ads.txt in one of our previous articles, you can find here.

What is sellers.json?

Sellers.json is the next step to further increase transparency in the programmatic ecosystem. Let’s imagine a coin. For a while, only one side of the coin was visible – the publishers' side (ads.txt). Now, with sellers.json, we will see the other side as well – seller side (SSPs or intermediaries and exchanges).

Both files– ads.txt and sellers.json– have the same goal: provide information about buyers, sellers, and resellers to know how the ad inventory is being sold.

How does sellers.json work?

Sellers.json’s file works like an identification card of all legal entities, which participate in the selling process.
This gives more info about who is going to receive the money and who is paying to whom. In simple terms, the Sellers.json file is for SSPs and exchanges and includes information about the relationship with their publishers.

There are two MANDATORY things, which have to be included in sellers.json file:

1. Seller’s ID;
2. Seller’s Type (Intermediary, publisher, or both).

Other information, like publisher’s domain or the name of the legal entity, can be confidential in some cases .

Sellers.json file example:


What are the differences between sellers.json and ads.txt?


How are Open RTB and supply chain object related?

Let’s imagine a situation: a user enters the website, and the ad request is sent to SSPs or ad buyers. This ad auction is a process of open RTB (real-time bidding) that allows displaying ads to a user based on geolocation, demographic, or behavioral attributes.

Supply Chain Object is a part of this ad request, which later on is represented in the sellers.json file. This allows buyers to know which intermediaries are involved in the process of selling ad inventory.

How does supply chain object work in reality?

For example, you, as a publisher who is creating quality content, chose Setupad as a way to increase your ad revenues and trust with your ad inventory.

We, however, sell your ad inventory through one of our partners- OpenX. Then ad buyers are bidding on ad impressions in real-time.

At this time, the supply chain object collects information about OpenX and Setupad.

Then ad buyer who won in the ad auction can check OpenX sellers.json file to see if Setupad was the authorized seller of your ad inventory.

What does sellers.json file mean for publishers?

The good news is that you, as a publisher, don’t need to worry about hosting sellers.json file. This is the responsibility of Setupad and our exchange partners.

This file is more relevant for ad buyers to understand if the seller was authorized to sell publishers ad inventory.