OpenRTB is the IAB Tech Lab specification for real-time bidding — the message format and protocol by which an ad exchange asks demand-side platforms to bid on an impression and receives their responses, in the tens of milliseconds before a page renders. It is the machine interface the programmatic advertising market actually runs on.
OpenRTB
OpenRTB specifies the bid request and bid response that move between an exchange and its bidders. It is one of the most widely implemented machine-to-machine contracts in existence — billions of times a day, between thousands of counterparties — and almost none of it is reachable by a developer without a signed agreement.
- Bid request and response - A typed message describing the impression, the context, the user signals and the floor.
- Counterparty integration - Endpoints are private and negotiated; there is no public portal, because there was never a self-serve buyer.
- Consent carried inline - The IAB TCF consent string travels in the request, which makes it a rare piece of machine-readable permission.
- Latency as a design constraint - Everything about the format is shaped by having tens of milliseconds to decide.
OpenRTB explains the central finding of The State of Marketing & Advertising APIs: advertising and programmatic is the largest segment in that market and the lowest-scoring on published contracts, at 22.2%. It is not that the segment lacks a machine interface. It has an excellent one, standardised and universally adopted — and it is private, which is a different thing from being published, and increasingly a different thing from being usable by an agent.
Referenced in API Evangelist papers
This standard shows up in my published research. These reports read the machine-readable evidence provider by provider — and put this standard in the context of a real sector.
The State of Marketing & Advertising APIs
The machine interface programmatic advertising actually runs on — deeply standardised, entirely private, and the reason the largest segment in that market publishes contracts 22.2% of the time.
