SSP, or Supply-Side Platform, is a technology platform that connects publishers and advertisers in the digital advertising ecosystem. It allows publishers to manage and sell their ad inventory to multiple ad exchanges and demand-side platforms, while providing advertisers with access to a wide range of premium ad placements. SSPs use advanced algorithms and real-time bidding to optimize ad placements and maximize revenue for publishers, while also providing advertisers with valuable targeting and reporting capabilities. In short, SSPs serve as the bridge between publishers and advertisers, facilitating the buying and selling of digital ad space in a seamless and efficient manner.