An SSP — supply-side platform — is the selling-side software in the programmatic advertising ecosystem. Publishers (websites, apps, venue networks) use SSPs to expose their inventory to ad exchanges, where DSPs bid on it in real-time auctions.
For programmatic DOOH, the major SSPs are Vistar Media, Place Exchange, Hivestack, Adomni, and Reverb. Each aggregates inventory from venue networks across the country and exposes that inventory through standard programmatic pipes. A cannabis brand running a programmatic DOOH flight through Vistar Media is buying inventory across many venue networks simultaneously, with venue-level frequency caps and dayparting controlled at the DSP layer.
Highfloor operates as both a direct seller of curated bar TV inventory and as a buyer of programmatic DOOH through the major SSPs. The two channels stack — direct curation for the strategic spine of a campaign, programmatic for the broader awareness layer.