OpenRTB

OpenRTB is an open standard for real-time bidding in programmatic advertising. It provides a common protocol for the automated buying and selling of ad impressions as auctions occur in real time, primarily through JSON messages that move between demand-side platforms (DSPs), supply-side platforms (SSPs), ad exchanges, and publishers.

The standard was developed under the auspices of the IAB Tech Lab with broad industry participation. It has evolved through multiple versions to support new ad formats, privacy requirements, and bidding logic, helping to reduce bespoke integrations and improve interoperability across participants.

In operation, a publisher's inventory is described in a bid request and sent to participating buyers. The bid request includes impression details, context, user and device information, and any constraints. DSPs evaluate the request, select a bid price, and respond with a bid and creative information. The ad exchange or SSP coordinates the auction and, after selecting a winner, serves the winning ad.

OpenRTB supports multiple formats, including display, video, and native advertising, with extensions to handle audio and other formats as needed. It is widely used in the programmatic ecosystem and is designed to enable interoperability across different platforms and markets.

Privacy and compliance are integral, with fields and mechanisms to convey user consent and regulatory restrictions (such as GDPR or regional privacy laws). Ongoing updates address fraud, transparency, and control over data sharing, reflecting evolving industry concerns.