Video Ad Serving Template (VAST) 4.1

Posted by Steven Poyser On November 12, 2018 Research & Resources

This revision of VAST includes updates that addresses most of the gaps identified in VAST 4.0. The Digital Video Technical Standards Working Group expects VAST 4.1 to be the first version of VAST4 to be widely adopted. The following are highlights of the changes introduced in VAST 4.1:

  • Verification: Changes that enable verification to be supported in a non-VPAID architecture (separated from media file). Also includes changes necessary to work with Open Measurement.
  • Digital Audio Ad Serving Template (DAAST): With VAST 4.1, DAAST has been merged into VAST.
  • Ad Requests: VAST is a response protocol. 4.1 now includes a basic Ad Request specification, based on macros.
  • Server-Side Ad Insertion (SSAI) related changes: VAST 4.1 includes minor changes to how headers should be handled. The “Ad Request” section is also relevant to SSAI use cases.
  • Deprecating Video Player Ad-Serving Interface Definition (VPAID): With VAST 4.1 we are taking the first steps to officially deprecate the use of VPAID.
  • AdServingID: A field to simplify comparing data about a video impression across the various systems involved with the delivery and tracking of the impression.
  • VAST Interactive Templates: Address the need for interactive ads without ad delivered executable code.
  • Closed Captioning: Standardizing the delivery of Closed Captioning files.


For more details, please download the VAST 4.1 specification below or visit the IAB Tech Lab website.


Steven Poyser