An SSP is the publisher-side counterpart to a DSP — software that manages and sells a publisher's ad inventory across exchanges and buyers, maximizing yield on each impression.
Definition
SSPs expose publisher inventory to demand sources, run or connect to auctions, apply floor prices and deal logic, and route the highest-value demand to each impression. In the agentic era, SSPs are building publisher-side sales agents — software that represents inventory to buyer agents over protocols like AdCP, answering queries and negotiating terms machine-to-machine.
Why it matters
The sell side determines what buyer agents will actually be able to discover and transact: a publisher whose inventory is legible to agents — well-described, honestly priced, protocol-accessible — captures agentic demand that opaque inventory misses. For buyers, SSP behavior (fees, auction mechanics, inventory description quality) remains a meaningful chunk of where each media dollar leaks or lands.
In agentic execution
As sell-side agents make inventory machine-negotiable, the buy side needs its own governed execution — objectives, guardrails, approvals. That supervised-agent discipline is Adlyse's operating model.
Related terms
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