Real-Time Bidding (RTB) is an automated auction where ad impressions are bought and sold in real time, allowing advertisers to bid for inventory based on user data. RTB takes place within milliseconds, determining the winning ad as a webpage load.

RTB increases ad efficiency by enabling precise targeting at scale. For advertisers, RTB optimizes spend by ensuring that each impression is shown to the highest-bidding, most relevant ad, maximizing engagement opportunities.