Reference / Glossary / Infrastructure and standards
Ad Exchange
A marketplace that connects buyers and sellers of programmatic inventory and runs the auction between them. Originally a distinct layer between SSPs and DSPs, exchanges have mostly merged into SSPs. Google's AdX, now part of Google Ad Manager, is the largest and the subject of the April 2025 ruling in the US Department of Justice's ad tech antitrust case, which found Google illegally monopolized publisher ad servers and ad exchanges.
Cite this entry:
Agency Echelon. "Ad Exchange." Agency Echelon Reference, reviewed October 2026. https://agencyechelon.com/reference/glossary/ad-exchange/