What Is DSP? Demand-Side Platforms
A demand-side platform (DSP) is a system used by advertisers allowing them to buy mobile, search, and video ads from a marketplace on which publishers list advertising inventory. These DSPs allow for the management of advertising across many real-time bidding networks, as opposed to just one, like Google Ads. Together with supply-side platforms, DSPs enables programmatic advertising.
Read more here.
What Is Programmatic Advertising?