Programmatic advertising has changed a lot in the nearly 20 years since the first RTB ad auction.

On the surface, programmatic is just the automated buying and selling of digital ads. Under the hood, there’s a complex, high-speed auction system that decides in milliseconds which ads appear across display, video, CTV, audio, retail and other online media.

And now, generative AI is starting to transform that process.

Programmatic systems need to evaluate impressions in the milliseconds it takes for pages to load and ads to render with numerous players in the middle.

Publishers generate bid requests for their inventory. Sell-side platforms (SSPs) package and route them to buyers. Demand-side platforms (DSPs) decide whether to bid and at what price. Agencies set up and manage campaigns based on what marketers want to achieve, and ad exchanges or SSPs run real-time auctions that match supply and demand across billions of daily transactions.