What is supply path optimization (SPO)?
Supply path optimization (SPO) is a buyer's practice of choosing the cheapest, most transparent and highest-quality routes to the same inventory, and cutting the rest. Because one impression may be offered through several SSPs and resellers, buyers analyse fees, win rates, fraud and data to pick fewer, more direct paths. It reduces cost, duplication and fraud risk.
Supply path optimization became necessary after header bidding multiplied the number of ways to reach the same impression, creating bid duplication. A buyer might see the same ad slot five times from five sellers, each taking a fee. SPO uses ads.txt, sellers.json and the supplyChain object to map paths, then favours direct sellers and partners with lower take rates.
The Trade Desk's OpenPath (direct publisher connections) and similar programmes are examples. The mirror image on the sell side is demand path optimization, where publishers trim underperforming buyers and intermediaries.