In programmatic advertising, a Demand-Side Platform (DSP) is a software used by advertisers to purchase ad inventory programmatically across the web, mobile, apps, video, and social media within advertiser-defined parameters. It allows advertisers to easily manage their campaigns and maximize their ROI by connecting them with multiple supply-side platforms (SSPs), ad exchanges, and ad networks at once. By doing so, DSPs let advertisers buy impressions from a greater pool of potential publishers and allows buyers to set the bidding range to maximize their revenue. DSPs provide similar functionality and technology as SSPs, but are used by advertisers to help optimize and get the best offer for their campaigns (aka maximize yield).
In programmatic ad buying, when consumers click on a publisher’s website, the publisher puts the ad impression up for auction through header bidding and one or more SSPs. Then, the DSP bids on behalf of the advertiser for that impression based on campaign’s strategies, budget, creative sizes, and other factors. The publisher automatically assigns impressions to the winning bidder -the advertiser/DSP offering the highest CPM (cost per mille, or the cost per one thousand advertising impressions).
https://digitalmarketinginstitute.com/blog/your-ultimate-guide-to-programmatic-advertising-terms