What Is Sellers.json? A Detailed Guide for Publishers

Brock Munro
January 26, 2024
March 20, 2024
What Is Sellers.json? A Detailed Guide for Publishers

Ad fraud is one of the biggest challenges in the digital advertising ecosystem. It is estimated that nearly 18% of ad impressions served in the United States (US) alone are fraudulent. It is estimated that in 2023, ad fraud caused advertisers to lose up to $88 billion.

In 2019, the Interactive Advertising Bureau (IAB) introduced sellers.json as a technical specification to increase trust and transparency in the programmatic supply chain. It does this by allowing advertisers to verify the authenticity of direct sellers and intermediary sellers of ad inventory. It prevents unauthorized reselling of inventory and mitigates the risk of ad fraud.

Without sellers.json, it becomes easy for fraudsters to hide their identities and exploit the programmatic supply chain, specifically on the sellers’ side, to rob legitimate advertisers and publishers of billions of dollars. They do this by using automated tools to generate fake impressions or clicks on ads, which results in financial loss to advertisers and publishers.

This article explains in detail what is sellers.json, how it works, and the benefits it offers publishers.

Table of contents:

What Is Sellers.json?

How Does Sellers.json Work?

Benefits of Sellers.json for Publishers

How to Implement Sellers.json?

Sellers.json Example

Sellers.json vs Ads.txt

Sellers.json vs SupplyChain Object

Future of Sellers.json in Programmatic Advertising

Final Thoughts

What Is Sellers.json?

Sellers.json is a published and accessible text file containing the list of entities who are either direct sellers or intermediaries in the sale of ad inventories. It is hosted on the websites of supply-side platforms (SSPs) or ad exchanges.      

Every legitimate entity’s name (individual or business name), domain name, and seller ID are entered in the .json file. This information allows advertisers to confirm the authenticity of sellers in the programmatic supply chain. 

Sellers.json also enables them to identify intermediaries participating in selling of a bid request. In short, the json file offers transparency about the entities selling digital advertising inventory.

How Does Sellers.json Work?

Sellers.json requires SSPs and ad exchanges to publicly disclose the sellers they represent, including publishers, intermediaries, and resellers and the identifiers of those sellers within their systems.

Sellers are required to share their individual or business name, along with the name of their domains. They also have to provide seller IDs for quick identification of the final sellers of bid requests. 

The Sellers.json file contains multiple fields including:


This is a 16-digit number unique to each seller which also appears in the ads.txt file. This is a mandatory field.


This identifies whether a seller is a publisher, an intermediary, or both. Publishers are the owners of the inventory, and the ad network pays them directly. Intermediaries, on the other hand, do not own the inventory. They do not receive direct payment from the ad network. Certain sellers are involved in both types of inventory selling—direct and intermediary—and are classified as “Both”. Seller_type is also a mandatory field.


The name of the legal entity that receives payment for the inventory sold under a given seller ID. This field can be optional if a seller chooses to keep its identity confidential in the field is_confidential.


The business domain name of the legal entity that is paid for the inventory sold under a given seller ID. Sellers do not have to fill in this information if they do not have a domain name/web presence or want to keep their identity confidential.

Fields Types Description
seller_id Required The unique id of the seller
Is_confidential Optional Informs whether the identity of the seller is confidential. 1 is used to indicate confidential; 0 for non-confidential.
seller_type Required Publisher, intermediary, or Both
name Required when is_confidential is 0 Name of the business
domain Required when is_confidential is 0/when the seller has a domain name The domain name of the company
How Does Sellers.json Work

Benefits of Sellers.json for Publishers

Not only advertisers but publishers also benefit from tapping into sellers.json. Some of these benefits are:

Assurance and Control

Ad inventory quality is a major concern for advertisers using programmatic advertising to reach their target audience. Through sellers.json, publishers can assure advertisers about the quality of their inventory. It also allows them to maintain better control over their inventory distribution, which helps them prevent unauthorized resale of their impressions.    


Sellers.json enables publishers to understand the supply chain and the entities involved in selling their ad inventory. This makes the process transparent for them. Also, by making their information visible to advertisers, publishers make the buying process transparent for ad buyers as well. This increases trust in the supply chain.  

Brand Reputation

Ad fraud damages the reputation of publishers, which causes a significant drop in their revenue. Sellers.json ensures that only authorized digital sellers or intermediaries are a part of the advertising ecosystem. This reduces ad fraud and improves brand reputation. Sellers listed in the sellers.json file are also seen as premium publishers.        

Increase in Revenue

Reduced ad fraud, better transparency, and improved trust will ultimately lead to advertisers spending more on advertising. This will eventually translate into more revenue for publishers. Afterall, everyone involved in a marketplace transaction benefits from an environment of trust and security.

How to Implement Sellers.json?

Different ad exchanges have their own sellers.json implementation process. Publishers tapping into Google Ad Exchange to sell their ad inventory can follow these steps to list their information on the Google sellers.json file:

  1. Go to Google Ad Manager
  2. Select Admin > Global Settings
  3. Select Ad Exchange account settings
  4. Enable “Sellers.json transparency.”
  5. Save the settings
How to Implement Sellers.json?

After this, a publisher’s name, business domain, and their seller id will appear in the Google sellers.json file, allowing advertisers to access this information. 

Here is the content of Google’s sample seller.json file.

seller.json file code

Sellers.json Example

The information in the sellers-json file appears in this format:

For Publishers

“seller_id”: “1987654321”,

 “name”: “Digital Advertising Inc”,

 “domain”: “Digitad.inc”,

  “seller type”: “PUBLISHER”

If the publisher chooses to keep their identity confidential, the name and domain will not appear.

For Intermediary

“seller_id”: “8755792561”,

 “name”: “Stream Up”,

 “domain”: “streamup.com”,

  “seller type”: “Intermediary”

Business domain name is omitted when the intermediary does not have a web presence, and the name and domain do not appear when they choose to keep their identity confidential.

Sellers.json vs Ads.txt

Sellers.json is a publicly accessible ledger that contains information on the authorized sellers, intermediaries, and resellers.

Ads.txt, short for authorized digital sellers, is also an initiative of IAB Tech Lab, like sellers.json. It enables publishers to declare sellers that are authorized to sell their ad inventory.      

Another difference between the two is that while ads.text is placed on the publisher’s website, the sellers.json file is hosted by SSPs and ad exchanges.

Ads.text is used only by publishers; it offers no information about who receives the payment from the advertising system. Sellers.json, on the other hand, reveals the receiver of the payment – whether it is the reseller, ad exchange, or SSPs.

Sellers.json vs SupplyChain Object

In 2019, along with sellers.json, IAB Tech Lab introduced another specification, the OpenRTB SupplyChain Object..

SupplyChain Object enables buyers to identify every active seller and reseller during the bid request. It is composed of a set of nodes—each node represents a specific entity involved in selling of bid requests. The object works together with sellers.json and ads.txt.

Intermediaries that are not involved in handling payment, such as client-side header bidding (including in-app header bidding and video header bidding) are not included in the SupplyChain Object.

Unlike sellers.json, SupplyChain Object works on the demand side platform (DSP) of the advertising system. One of its key advantages is that it offers complete visibility into the supply chain from beginning to end—from the inventory source to the ad buyer. 

It therefore, provides insight into everything that is happening at every stage of the transaction. Sellers.json does not offer this advantage.  

Future of Sellers.json in Programmatic Advertising

Programmatic advertising is the future of digital advertising. Trust and transparency, however, are critical for its sustained popularity and acceptance by publishers and advertisers. Specifications and frameworks such as sellers.json and Unified ID 2.0 will continue to play a vital role in ensuring that.

Several reports have predicted that ad fraud, like domain spoofing, will be a bigger menace in the future. As a result, it is very likely that advertisers and publishers will have to lean even more heavily upon sellers.json if they want to reduce ad fraud risk and cut down losses.

In the longer run, sellers.json is expected to help improve the overall quality of digital advertising by a significant margin.

Final Thoughts

With ad fraud on the rise, it has become essential for advertisers and publishers to make sellers.json a crucial part of their programmatic advertising ecosystem. 

Sellers.json allows publishers to share the information about direct sellers, intermediaries, and resellers of an ad inventory in a publicly accessible text file. Advertisers can use this information to ascertain whether or not the seller is legitimate. Sellers.json helps effectively fight ad fraud as well as boosts publisher revenue.

Publift has been helping publishers increase their revenue by an average of 55% with its cutting-edge technology and world-class customer support. Our impartial and ethical guidance enables publishers to make their programmatic advertising process more transparent and gain the most out of their ad inventory. 

Contact us today to know how we can help you attain your digital advertising goals.

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