Which OpenRTB version is most used?
Answer
OpenRTB 2.5 and 2.6 carry the overwhelming majority of real-time bidding traffic; there are no reliable public numbers splitting the two, but 2.6 adoption keeps growing as CTV pod bidding and first-class privacy fields pull integrations forward, while plenty of production endpoints still speak 2.4 or 2.5. OpenRTB 3.0 remains a small fraction of traffic despite being final since 2018. Practically, build and validate against 2.6 (ideally a specific dated snapshot), and expect to keep accepting 2.5-shaped requests, with the promoted fields still in ext, for a long time.
Go deeper
More questions on privacy, identity, supply chain, and versions
- How do I pass GDPR consent in an OpenRTB bid request? Set regs.gdpr to 1 when the request is subject to GDPR and put the TCF consent string in user.consent.
- How do I pass a GPP string in OpenRTB? Put the Global Privacy Platform consent string in regs.gpp and list the applicable section IDs in regs.gpp_sid.
- GPP vs us_privacy: which should I send? Send GPP (regs.gpp plus regs.gpp_sid) where your partners support it; the US Privacy signal was deprecated by IAB Tech Lab on January 31, 2024 in favor of GPP.
- How do I signal CCPA in OpenRTB? Put the US Privacy string in regs.us_privacy, which is a first-class field in OpenRTB 2.6; on 2.5 and earlier it travels as regs.ext.us_privacy per the IAB extension.
- How do I signal COPPA in an OpenRTB request? Set regs.coppa to 1 when the request is subject to the COPPA regulations established by the US FTC, and 0 when it is not.
- What is the DSA extension in OpenRTB? The DSA transparency extension carries EU Digital Services Act ad-transparency data through OpenRTB 2.x ext blocks.
All 93 questions are listed in the OpenRTB FAQ.