The IAB standard XML format for delivering video ads from an ad server to a video player, including the media files, tracking events, and click-through. VAST 4.x is current and adds server-side ad insertion support, the Open Measurement interface, and mezzanine files for CTV. VPAID, the older interactive extension, has been deprecated in favor of SIMID and OMID.
Cite this entry:
Agency Echelon. "VAST." Agency Echelon Reference, reviewed September 2026. https://agencyechelon.com/reference/glossary/vast/