Definition & Explanation

An ad exchange is a digital marketplace where publishers list their available ad inventory and advertisers bid on it in real time. Acting as the core technology layer in programmatic advertising, ad exchanges use real-time bidding (RTB) to match ads with available spaces on websites, apps, and other platforms — with each auction completing in roughly 100 milliseconds. Unlike ad networks, which act as intermediaries, ad exchanges give both buyers and sellers more direct control over pricing and targeting.