OpenRTB (Real-Time Bidding)

OpenRTB VersionsSupport for PrivacyResources and Related DocumentsExtensions and Addendums

Announcing OpenRTB 2.6 for Public Comment

The 2.6 version of OpenRTB is available for public comment until February 7, 2022.

The flagship features of OpenRTB 2.6 enable CTV publishers to better monetize their inventory. It achieves this by bringing the buying and selling of CTV inventory more in line with that of traditional TV advertising with the introduction of structured, dynamic and hybrid ad pods and it intoduces Network and Channel objects that enable publishers to better describe their inventory.

In addition to the benefits for CTV, OpenRTB 2.6 also enables the use of AdCOM within OpenRTB and it brings improved signalling to IAB Tech Lab taxonomies to help better support contextual advertising.

View OpenRTB (Public Comment)

About OpenRTB

Real-time Bidding (RTB) is a way of selling media that enables an individual advertising opportunity (ad impression) to be put up for bidding in real-time. OpenRTB is the communication protocol that enables real-time bidding. It was designed to spur growth in RTB marketplaces by providing an open industry standard for communication and interoperability between buyers and sellers in the digital advertising industry.

These standards provide the protocol for real-time bidding transactions and include standardized and consistent ways to communicate necessary information about the ad impression; for example the publisher information, the creative standards and sizes of the unit, the fraud mitigation signals that have been applied and other additional information that buyers require to make a bidding decision.


OpenRTB Versions

VersionRelease Date
OpenRTB 2.5 (PDF)
OpenRTB 2.5 included updates that integrated industry trends and allowed for improvements in programmatic technology. Release highlights include:

  • IAB New Ad Portfolio Support – integrating flexible aspect-ratio based ads into the bid object

  • Video Placement Type Support – adding visibility into what type of placement a VAST (video ad serving template) tag is running in accordance to the IAB digital video glossary

  • Header Bidding Support – allowing for a signal when a bid request is originated from an upstream decisioning implementation like header bidding

  • Historic Metrics Support – whereby exchanges can pass historic metrics such as viewability or click through rate


December 2016
OpenRTB 2.4 (PDF)
OpenRTB 2.4 main improvements:

  • Video skippability support

  • SSL Support

  • New audio object created

  • Increased location support

March 2016
OpenRTB 2.3.1 (PDF)
Provided an update to the specification addressing two typos:

  • Section 3.2.13 - in the user object, the buyer ID attribute has been corrected to "buyeruid."

  • Section 4.4 - The ${AUCTION_BID_ID} macro has been corrected to be substituted with the “BidResponse.bidid” attribute.

June 2015
OpenRTB 2.3(PDF)
The OpenRTB 2.3 specification was the first version updated to provide support for native ads. This was one of the most significant updates to OpenRTB as it allows for native ads to be targeted, optimized, and transacted on programmatically, reducing workload on publishers and advertisers alike. Release highlights include:

  • Native ad placements must be included directly into the impression object in order to be passed through the bidstream.

  • Allows for the inclusion of metadata (title, urls, data, img files) in the native request. The buy side now has the ability to describe the unit that’s being bid on and the supply side is able to define which fields are available and required in order to assemble the native ad.

  • Updates to the style of the document including improved diagrams and revamped table format to support the continued commitment to OpenRTB.

January 2015
OpenRTB 2.2(PDF)
OpenRTB 2.2 provided for improved PMP and non-intentional traffic support. With bot traffic becoming an increasing concern to both the buy and sell sides, OpenRTB 2.2 allows for all parties to be able to provide real-time feedback on ads to determine and block non-human traffic. Release highlights include:

  • Support to the allow for the differentiation of secure and nonsecure inventory

  • Exhaustive Deal ID support for Private Marketplaces

  • Improved backing for new types of mobile and video inventory

  • Ability for buyers to alert sellers in real time about suspected bot traffic

  • COPPA regulation support



April 2014
OpenRTB 2.1 (PDF)
OpenRTB 2.1 provided for improved VAST video, tablet and location targeting support. Release highlights include:

  • IAB Tier-2 category support

  • Recognition of tablet inventory
  • VAST video across RTB; the video object must represent an impression as either banner, video or both
  • Location source support; differentiation of GPS derived and zip code value targeting

October 2012
OpenRTB 2.0 (PDF)
OpenRTB 2.0 provided unified support for display, mobile, and video capabilities. This was a significant step forward for programmatic as allows for the harmonization of mobile and desktop advertising. Release highlights include:

  • VAST ad unit support

  • Improved geographical data definition

  • Increased cross-channel support for mobile and desktop through a common API language

  • Improved 3rd party data segment support for audience targeting

  • Enhanced attribution support; inclusion of device IDs in mobile & mobile app parameters

January 2012

OpenMedia and OpenRTB 3.0

OpenRTB 3.0 is the largest overhaul of the OpenRTB protocol since its inception in 2010. The purpose of this major update is to meet the market’s demand for security, transparency, authentication, and trust in programmatic advertising. New structure for programmatic specifications means that where OpenRTB 2.x was previously used alone, now OpenRTB 3.0 AND AdCOM 1.0 should be used in tandem.

Support for Privacy

Apple announced a number of privacy related updates in iOS 14, which impact how in-app advertising and attribution works. We have released a set of OpenRTB extensions to support these updates:

The IAB Tech Lab Releases Updates To Three Programmatic Protocols (Blog Post)

IAB Tech Lab Releases Two Major Updates to OpenRTB (MediaPost)

IAB Tech Lab Releases Protocols For OpenRTB (Press Release)


Extensions and Addendums

OpenRTB Dynamic Native Ads

Download the OpenRTB Advisory – GDPR (PDF)

OpenRTB Security Advisory 15-01 (PDF) Released December 2015: Guidance for DSPs and SSPs to mitigate botnet attack optimization tactics.

OpenRTB Extensions

When individual companies want to solve a problem that isn’t covered by the core OpenRTB (or AdCOM) specs, they can use OpenRTB’s (and AdCOM’s) extensions mechanism to implement a solution. They can work on it privately and limit usage between themselves, or they can make the OpenRTB “Community” aware of this extension to gauge the usefulness of that extension. After a period of time, if there is sufficient support, the extension can be made part of the “official” specs by getting approval from the Programmatic Supply Chain Working Group. This path is slightly different for OpenRTB 2.x and 3. So with 2.x the extension gets moved to the “Official extensions” folder, while with 3.x it gets added to the OpenRTB/AdCOM specs and released as a new version of the spec. Extensions are available here for industry to use and collaborate.


Developed by the Programmatic Supply Chain Working Group


IAB Tech Lab Contact

Jill Wittkopp
Senior Director, Programmatic & Software Products 
support@iabtechlab.com