Standards

Supply chain object

Also called schain.

A field in the bid request listing every party that handled the impression on its way to the buyer.

Each node names a seller and its ID. Buyers check the chain against sellers.json and prefer short, complete chains. A publisher’s ad server should build the chain from the publisher’s own sellers.json entries and pass it on intact.

Each hop adds a node. The buyer reads the chain, checks every node against sellers.json, and prefers short ones.