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DOOH GlossaryDSP, SSP & Exchange

Ad Exchange

A real-time auction venue that matches DSP buyers with SSP sellers, the marketplace where ad impressions are priced and cleared.

An ad exchange is a real-time auction marketplace where DSPs bid on impressions exposed by SSPs. Historically, exchanges were a separate layer between DSP and SSP (Right Media, AdX, OpenX), but in modern programmatic the SSP-and-exchange roles have largely merged, Magnite is an SSP and an exchange; FreeWheel is an SSP and an exchange.

Mechanically, every exchange runs the same loop. A bid request lands describing the impression (publisher, format, dimensions, audience signals, floor price). The exchange fans the request out to N DSPs in parallel, waits up to ~80-100ms for responses, picks the highest bid above the floor, and returns the winning creative. The whole loop sits inside the RTB protocol; OpenRTB 2.6 is the current spec version.

Auction mechanics matter. First-price auctions (the buyer pays what it bid) are now the dominant DOOH and CTV format; second-price (pay one cent above the second-highest bid) used to dominate but was deprecated industry-wide circa 2019 because of trust-and-transparency concerns. Some exchanges support sealed first-price; others support hybrid models with soft floors.

Google's AdX is the largest exchange globally; on DOOH specifically, Vistar Media's exchange and Place Exchange are the dominant supply-side specialists. Trillboards integrates with multiple DOOH exchanges through its partner SDK.

Authoritative reference

IAB Tech Lab, OpenRTB

See also

DSP (Demand-Side Platform)
A buy-side ad-tech system. Advertisers (or their agencies) log into a DSP to set targeting, budgets, and creatives, then bid into exchanges.
SSP (Supply-Side Platform)
A sell-side ad-tech system. Publishers and screen networks expose their inventory through an SSP, which auctions it to DSPs.
RTB (Real-Time Bidding)
The auction protocol that prices ad impressions in ~100ms, bid request out, bid response in, winning creative served.
OpenRTB 2.6
The current IAB Tech Lab spec for real-time bidding. Adds native DOOH support, CTV pod-level requests, and ID-less identity primitives.
Header Bidding
Pre-auction technique where multiple SSPs bid in parallel before the ad-server call, invented on the web, ported to CTV, now reaching DOOH.

Reference docs

Building against Trillboards?

Our developer reference covers the DSP API, partner SDK, proof-of-play verification, and the sensing pipeline that powers buyer-grade audience signals.

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