Programmatic inventory that any buyer with access to the exchange can bid on in real time, with no prior agreement between buyer and seller. The open auction is the largest pool of programmatic supply and the lowest-priced, and also the one most exposed to fraud, low-quality sites, and unclear supply paths. Most sophisticated buyers restrict open-auction buying with inclusion lists and Supply Path Optimization.
Used in The Signal
Cite this entry:
Agency Echelon. "Open Auction." Agency Echelon Reference, reviewed September 2026. https://agencyechelon.com/reference/glossary/open-auction/