SSP (Supply-Side Platform)

A supply-side platform (SSP) is the technology publishers and app developers use to sell their ad inventory programmatically. It offers each impression to many buyers at once, sets price floors, applies the publisher's content rules and aims to maximize revenue per impression.

The SSP is the counterpart to the demand-side platform: the DSP represents advertisers and decides what to bid, while the SSP represents publishers and decides which bid to accept. They meet in the ad exchange. App advertisers do not usually contract with SSPs directly; their DSP reaches SSP inventory through exchanges.

For buyers, the SSP side matters because floors, auction rules and publisher restrictions all affect price and win rate. Different SSPs also carry different inventory quality, so reviewing performance by SSP or exchange — and preferring direct, transparent supply paths — is a simple and effective optimization for any advertiser buying programmatically.