Video Ad Serving Template

Video Ad Serving Template (VAST) is a specification defined and released by the Interactive Advertising Bureau (IAB) that sets a standard for communication requirements between ad servers and video players in order to present video ads.

It is a data structure declared using XML.

VAST has 8 versions: 1.0 (deprecated), 1.1 (deprecated), 2.0, 2.0.1 (the schema version as the official VAST 2.0 schema), 2.6, 3.0, 4.0, 4.1 and 4.2.

Request
In order to play a video ad in a video player, the video player sends a request to a VAST ad server.

It is a simple HTTP based URL that typically appears as follows: http://www.example.com/?LR_PUBLISHER_ID=1331&LR_CAMPAIGN_ID=229&LR_SCHEMA=vast2-vpaid

Response
The ad server responds with a VAST data structure that declares these parameters:
 * The ad media that should be played
 * How the ad media should be played
 * What should be tracked as the media is played
 * The companion ad that should be displayed alongside the master ad

For example, the above request returns the following response (trimmed):