Sellers.json

# Sellers.json

Sellers.json is an open-source, standardized digital ad fraud prevention and supply-chain transparency specification established by the Interactive Advertising Bureau (IAB) Tech Lab that requires programmatic Supply-Side Platforms (SSPs), advertising exchanges, and ad networks to publish a publicly accessible, machine-readable JSON directory file listing all authorized entities, publishers, and intermediary brokers from whom they source and monetize digital advertising inventory. Situated in the root directory of an ad tech platform domain (e.g., https://example-ssp.com/sellers.json), the file establishes an open corporate registry of verified media sellers.

Paired with complementary verification protocols like Ads.txt and the OpenRTB SupplyChain Object (schain), Sellers.json plays a transformative role in cleaning up the opaque, fraud-ridden programmatic advertising supply chain. Historically, digital advertisers bidding on programmatic ad exchanges had no way of knowing whether their money was going to legitimate news publishers or being skimmed by shadowy intermediary shell companies running domain spoofing scams. Sellers.json pulls back this curtain, allowing media buyers and programmatic verification algorithms to audit the complete financial lineage of every ad placement in real time.

The crisis of programmatic opacity and the IAB transparency trio

To understand the genesis of Sellers.json, media buyers must recall the severe crisis of confidence that engulfed programmatic advertising in the mid-2010s. The programmatic supply chain had become a convoluted maze of arbitrary resellers, unauthorized ad networks, and hidden intermediaries. Arbitrageurs routinely engaged in domain spoofing (falsely labeling low-quality pirate websites or bot farms as premier media outlets like The New York Times), siphoning billions of dollars in advertising budgets away from legitimate publishers.

To dismantle ad fraud and restore supply-chain integrity, the IAB Tech Lab engineered a trifecta of interlocking transparency specifications:

• Ads.txt (Authorized Digital Sellers): A text file published by publishers declaring which ad tech platforms are authorized to sell their ad inventory.
• Sellers.json: A JSON file published by SSPs and ad exchanges declaring who they pay for ad inventory (direct publishers vs intermediary resellers).
• OpenRTB SupplyChain Object (schain): A real-time bidstream data object that records every intermediary node that an ad bid request passed through from publisher origin to buyer. Together, these standards establish an unbroken cryptographic chain of verification.

Structural syntax and schema architecture of Sellers.json

A valid Sellers.json file must adhere to strict JSON schema definitions established by the IAB Tech Lab, containing an array of structured seller objects. Each seller entry contains standardized data fields that identify the entity receiving financial disbursement:

• seller_id: The unique identifier assigned to the seller within the SSP internal billing system, corresponding directly to the seller ID listed in publisher Ads.txt files and bidstream SupplyChain objects.
• name: The legal corporate name of the entity or business receiving payments.
• domain: The canonical business domain of the seller entity.
• seller_type: Categorizes the relationship as "PUBLISHER" (the entity owns and operates the website or app generating the ad impressions), "INTERMEDIARY" (a broker, monetization agency, or ad network that resells inventory), or "BOTH".
• is_passthrough: A boolean indicator noting whether the intermediary simply passes through payments without controlling ad inventory directly.

Preventing domain spoofing and combating arbitrage fraud

The primary operational mechanism by which Sellers.json eliminates ad fraud is supply-chain triangulation and automated bid validation. When a Demand-Side Platform (DSP) receives a programmatic bid request claiming to originate from a premier publisher, the DSP automated verification algorithms cross-reference all three transparency standards simultaneously in real time.

The algorithm checks the publisher Ads.txt file to confirm that the SSP is authorized to sell the inventory. It then inspects the SSP Sellers.json file to verify that the seller_id matches the publisher legal business name and is classified as "PUBLISHER" rather than an unverified "INTERMEDIARY." Finally, it audits the SupplyChain Object to confirm that the bidstream hops match the authorized path. If a shadowy broker attempts to inject spoofed inventory into the auction, the discrepancy triggers immediate bid suppression, starving fraudulent actors of capital.

The transparency penalty: Confidentiality versus corporate accountability

When Sellers.json was originally mandated, the specification permitted an optional field called is_confidential, allowing publishers and resellers to conceal their legal business name and domain from the public registry. Opaque intermediaries and privacy-conscious publishers utilized confidentiality flags to hide their monetization relationships, recreating the very opacity the standard was designed to eradicate.

However, the programmatic buying ecosystem responded with swift, severe economic enforcement. Leading programmatic media buyers and major agency holding companies established strict pre-bid filtering rules that automatically blacklist and block any bid request associated with a confidential seller ID in Sellers.json. Today, maintaining a transparent, non-confidential Sellers.json listing is mandatory for programmatic monetization; publishers and resellers who attempt to operate anonymously are effectively locked out of high-CPM enterprise advertising budgets.

Optimizing SPO (Supply-Path Optimization) with Sellers.json

In modern programmatic media buying, Supply-Path Optimization (SPO) is the strategic practice of consolidating advertising budgets onto the most direct, transparent, and cost-efficient programmatic routes to publisher inventory. In legacy setups, a single publisher inventory was often routed through five or six redundant SSPs and intermediary resellers, with each hop skimming a five to fifteen percent technology take-rate.

Media buyers utilize automated Sellers.json scrapers and graph analysis algorithms to map the entire programmatic supply topology. By analyzing seller types and intermediary hops, DSPs systematically prune convoluted, multi-hop reseller paths, routing bids exclusively through direct single-hop connections (where the SSP connects directly to a verified "PUBLISHER" seller). SPO eliminates intermediary tax fees, reduces auction latency, elevates win rates, and ensures that eighty to eighty-five cents of every advertising dollar goes directly to supporting working media and legitimate publishers.

Compliance monitoring, automated auditing, and validation workflows

Maintaining compliance with Sellers.json standards requires continuous operational governance by SSPs and ad exchanges. An SSP Sellers.json file must be updated in real time as new publisher accounts are onboarded or rogue accounts are terminated. Failing to update seller IDs or allowing discrepancies between internal billing databases and the public JSON file causes DSPs to drop legitimate inventory auctions, triggering massive revenue loss for publisher partners.

Ad tech engineering teams deploy continuous automated web crawlers that scan and validate Sellers.json files across the industry. Automated crawlers inspect JSON formatting syntax, verify domain connectivity, flag deprecated seller IDs, and alert ad operations teams to mapping errors. By enforcing rigorous, continuous compliance verification, the programmatic ecosystem fosters an open, verified marketplace where advertisers invest with confidence and publishers are fairly compensated for premium digital content.

Related terms

• Ads.txt: Strategic concepts, analytical methods, and operational frameworks related to sellers.json.
• Ad exchange: Strategic concepts, analytical methods, and operational frameworks related to sellers.json.
• Supply-side platform: Strategic concepts, analytical methods, and operational frameworks related to sellers.json.
• Programmatic advertising: Strategic concepts, analytical methods, and operational frameworks related to sellers.json.
• Ad fraud: Strategic concepts, analytical methods, and operational frameworks related to sellers.json.