Glossary
RTB
An auction mechanism where ad impressions are bought and sold individually, in real time, as a page or app loads.
Definition
An auction mechanism where ad impressions are bought and sold individually, in real time, as a page or app loads.
Why it matters
RTB is the actual auction happening under the hood of most open-exchange programmatic buying — understanding it explains why programmatic pricing is volatile and why the same audience can cost differently minute to minute.
Key consideration
RTB inventory quality varies enormously since it is open to any bidder. This is precisely why supply path optimisation and curated marketplaces exist — to filter what RTB alone does not.
Related terms
Practitioner notes
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