What is OpenRTB?
OpenRTB is the IAB Tech Lab's open technical standard for how buyers and sellers communicate in real-time bidding. It defines the format of bid requests and bid responses, including fields for the site or app, device, user, ad format, deals and supply-chain information, so any compliant DSP and SSP can trade with each other without custom integrations.
OpenRTB was first released in 2010–2011 and has been revised many times; version 2.5 and 2.6 are the most widely deployed, with 2.6 adding support for CTV ad pods and other video features. A companion standard, AdCOM, describes common objects such as ads and placements.
Because nearly every programmatic transaction uses it, OpenRTB is where industry changes land: the supplyChain object, consent fields for the IAB TCF and IAB Global Privacy Platform, and signals for new identifiers. The IAB Tech Lab maintains it with input from member companies.