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Bid transparency with the SupplyChain Object

The SupplyChain Object enables buyers and intermediaries to see all parties who are selling or reselling ad inventory. The object works together with ads.txt / app-ads.txt and sellers.json to provide transparency into the ads ecosystem.

  1. Publisher sends a bid request.
  2. Buyer receives bid request and data from the SupplyChain Object.
  3. Buyer looks up the identities of all intermediaries who resell inventory.
  4. Buyer crawls and verifies vendors authorized to sell inventory.

Google will automatically create the objects within an OpenRTB request or Google RTB protocol, if applicable.

How the SupplyChain Object works

The SupplyChain Object, otherwise known as schain, is a part of an OpenRTB bid request and consists of "nodes." Each node in the schain object represents a specific entity participating in the bid request, which includes all entities involved in the direct flow of payment for inventory.

// Example object
"schain": {
    "complete": 1,
    "nodes": [{
         "sid":"pub-1234567891234567", // Same seller_id for the publisher in sellers.json

Read OpenRTB’s developer documentation and IAB's documentation for further details.

The SupplyChain Object looks different depending on the way you work with buyers.

Publishers who sell directly with Google

For publishers who sell inventory directly through Ad Manager, AdMob, or AdSense, the schain object contains only one node for “” with the seller_id found in sellers.json.

Publishers who use Open Bidding

Publishers who use Open Bidding to work with third-party exchanges have two nodes in the schain object: one node for with the seller_id found in sellers.json and one node for the exchange yield partner.

Just as Google creates the node for before sending the bid request, the third-party exchange is responsible for adding their node before passing on the request.

All non-payment intermediaries

Intermediaries that don't handle payment are not included in the SupplyChain Object. This includes client-side header bidding, non-payment header bidding, and other mediation.

Multiple Customer Management publishers

Multiple Customer Management (MCM) lets publishers manage their clients’ AdMob accounts with the same visibility and control as the publishers themselves.

For parent and child publishers using AdMob MCM, the schain object will have one node with the child publisher’s seller ID, one node for the parent publisher, and the chain will be marked complete. For AdMob MCM, monetization occurs in the child publisher’s account. The child publisher is treated as the end publisher. 


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