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IAB Tech Lab Releases VAST 4.1 For Public Comment


Critical Updates to the Digital Video Ad Serving Template Include Support for Improved Ad Verification, Ad Creative Measurement, and Server-Side Ad Insertion & Integration of Audio Advertising

NEW YORK, NY (June 14, 2018) – The IAB Technology Laboratory today released VAST 4.1 for public comment, featuring significant advancements to the digital video ad serving template. Improved verification will allow for support within non-VPAID (Video Player-Ad Interface Definition) architecture, while also permitting VAST 4.1 to align with the Open Measurement Interface Definition (OMID) to better measure viewability of video ads on web. Upgrades for server-side ad insertion and the integration of DAAST (Digital Audio Ad Serving Template) are also key elements of the proposed specification.

Additional revisions tackle a range of technical issues, such as:

  • Ad Requests: VAST 4.1 takes the first steps to standardizing ad requests through the use of macros, which will help propagate context more easily, especially for server-side ad insertion and server-to-server communications.
  • Deprecating Video Player Ad Serving Interface Definition (VPAID): While VPAID will continue to be used in the near future, VAST 4.1 takes the first steps to officially deprecate its use – significantly simplifying video ad execution and improving consumer experience.
  • AdServingID: A required field has been added to simplify comparing data about a video impression across the various systems involved with the delivery and tracking of the impression, enabling better measurement and more.
  • VAST Interactive Templates: Recognizing the need for standardizing interactive ads without ad delivered executable code, especially in mobile and OTT environments, VAST 4.1 introduces the concept of interactive templates.
  • Closed Captioning: VAST 4.1 enables closed captioning by standardizing the delivery of closed captioning files.
  • Flash: With VAST 4.1, all references to Flash and Flash resources are being removed, reflecting discontinuation of Flash usage in ads.

VAST 4.1 is accompanied by OMID version 1.2 that adds support for web browsers and guidance to implement it for web browsers.

In order to help the industry transition to this new version, the IAB Tech Lab is working on a series of webinars and blog posts, as well as a VAST Compliance Program that will test and certify VAST 4.1 implementations.

“As the video landscape has evolved and grown, so have the technical complexities in delivery, measurement, and more,” said Dennis Buchheim, Senior Vice President, Technology and Ad Operations, IAB, and General Manager, IAB Tech Lab. “Once VAST 4.1 is adopted in the marketplace, we’ll see dramatically improved digital video and audio operations for buyers, sellers, and technical teams, making way for even greater growth for video.”

“VAST 4.1 with Open Measurement brings us closer to consistent measurement across all platforms, which has been an elusive goal,” said Joe Barone, Managing Partner, Brand Safety Americas, ‎GroupM. “These updates will make a meaningful difference to brand clients and will give them greater confidence in allocating more of their marketing budgets to video.”

The public comment period will run through July 14, 2018, after which the IAB Tech Lab Digital Video Technical Standards Working Group will evaluate the comments received, make any necessary revisions, and release a final version. Comments are being accepted via email to

To review the proposed specification, please go to To view OMID version 1.2 and implementation guidance for web, please go to .

About IAB Technology Laboratory

The IAB Technology Laboratory (“Tech Lab”) is a non-profit research and development consortium that produces and provides standards, software, and services to drive growth of an effective and sustainable global digital media ecosystem. Comprised of digital publishers and ad technology firms, as well as marketers, agencies, and other companies with interests in the interactive marketing arena, IAB Tech Lab aims to enable brand and media growth via a transparent, safe, effective supply chain, simpler and more consistent measurement, and better advertising experiences for consumers, with a focus on mobile and “TV”/digital video channel enablement. The IAB Tech Lab portfolio includes the DigiTrust real-time standardized identity service designed to improve the digital experience for consumers, publishers, advertisers, and third-party platforms. Board members include AppNexus, ExtremeReach, Google, GroupM, Hearst Digital Media, Integral Ad Science, Index Exchange, LinkedIn, MediaMath, Microsoft, Oracle’s Moat, Pandora, PubMatic, Quantcast, Telaria, The Trade Desk, and Yahoo! Japan. Established in 2014, the IAB Tech Lab is headquartered in New York City with an office in San Francisco and representation in Seattle and London.

IAB Media Contact
Laura Goldberg