What is RTB (Real-Time Bidding)?

Real-Time Bidding (RTB) is a form of programmatic advertising that enables the buying and selling of digital ad inventory through automated, instantaneous auctions. These auctions take place in milliseconds — every time a user loads a webpage, an RTB auction occurs in the background.

How RTB Works:

When a user visits a website, the publisher’s ad server sends a bid request to an ad exchange or SSP. This includes information about the available ad slot and anonymised user data. Advertisers or DSPs evaluate the opportunity and submit bids in real time. The highest bidder wins the impression — all within approximately 100 milliseconds.

Key Components:

• Ad Exchange / SSP: Marketplace where publisher inventory is auctioned
• DSP (Demand-Side Platform): Technology used by advertisers to participate in auctions
• Bid Request: Data sent by the publisher’s SSP describing the ad opportunity
• Bid Response: The advertiser’s reply with their bid price and creative
• Impression: A single instance of an ad being displayed

RTB allows advertisers to buy individual impressions based on their value rather than bulk inventory, enabling precise audience targeting. Publishers maximise yield by auctioning every impression to the highest bidder.