RTB (real-time bidding)
RTB (real-time bidding) is the auction system in which each ad impression is sold at the moment a page or app loads, to the buyer who bids the most for it.
It all happens before the page has finished loading: the publisher’s SSP sends a bid request with context data (the site, the format, the device, the approximate location), advertisers’ DSPs decide whether they are interested and how much to offer, and the ad exchange awards the impression and serves the winning ad. The most widely used protocol is OpenRTB, from the IAB Tech Lab.
RTB is the open form of programmatic buying; alongside it sit private marketplaces (PMPs) and programmatic guaranteed deals, in which publisher and buyer agree on price or volume in advance. In an open auction, audience data is what allows buyers to bid wisely: knowing which impressions are worth more to a brand and which are not worth a bid.
