← Glossary
VAST (Video Ad Serving Template)
IAB standard XML format for communicating video ad metadata between ad servers and players.
VAST is the IAB standard for delivering video ads to players. The ad server returns a VAST XML document containing creative assets, tracking beacons, click-through URLs, and error pixels. VAST 4.2 is the current version for CTV, supporting pod structure, multiple creatives, and verification extensions. Players fire quartile beacons (start, firstQuartile, midpoint, thirdQuartile, complete) for measurement.