A demand-side platform (DSP) enables advertisers to buy advertising inventory across different domains, apps, and video platforms.
DSPs are connected to an advertising exchange. An advertising exchange enables DSP to connect to a marketplace. Through the marketplace, users can buy specific ad inventory.
The buying process used to be facilitated by humans but with the advent of machine learning technologies, advertisers are able to bid on ad inventories in real-time. DSPs have helped facilitate an efficient means of buying ad inventory, optimization of ad spend, and real-time analysis of campaign performance.
DSPs are used in the programmatic buying realm and they work in tandem with an SSP (Supply Side Platform).