What are VAST and VPAID?

What are VAST and VPAID?


VAST is a Video Ad Serving Template for structuring ad tags that serve ads to video players. Using an XML schema, VAST transfers important metadata about an ad from the ad server to a video player. Initially launched in 2008, VAST has since played an important role in the growth of the digital video marketplace.

The early days of video consisted mostly of shared videos and other user-generated content. Success in monetizing this content with ads has produced the resources to improve the digital video marketplace. However, digital video has met a number of challenges along the way.

One challenge is a lack of quality control. Along with the IAB Video Player-Ad Interface Definition (VPAID), VAST can deliver ads programmatically or include ads with complex interactions. If a player isn’t programmed to accept VPAID ads, the ad cannot be executed. Even when the player does accept VPAID ads, performance may be slow and cause latency in load times. In the meantime, the audience experiences a delay or a malfunction in their viewing experience.

Publishers and ad vendors need a way to separate the video file from its interactive components to ensure that ads play in systems that cannot execute the interactive components. These ads should also execute more efficiently in players that are equipped to handle the interactions.

Another challenge, especially for broadcasters who are moving their content online, is the lack of a consistent identifier for creative that is maintained across systems. VAST offers a creative identifier, but it has been used inconsistently and one creative may use different identifiers for every system it passes through. A system-wide identifier is a requirement for broadcasters trying to maintain control over the ads they play.

VAST 4.0 has addressed these challenges along with a few others. As players begin to adopt the updates in VAST 4.0, digital video can expect to see smoother operation and continued growth.


The IAB’s Video Player Ad Interface Definition (VPAID) establishes a common interface between video players and ad units, enabling a rich interactive in-stream ad experience.

In-stream video advertisers have two important execution goals for the delivery of their video ad campaigns: a) provide viewers a rich ad experience, and b) capture ad playback and user-interaction details that report on the viewed ad experience. To achieve these goals in a world without common video player functionality, advertisers would have to develop multiple specialized versions of their ad creative for every unique video player—an expensive proposition that doesn’t scale well.

The Video Ad-Serving Template (VAST), another IAB specification, provides a common ad response format for video players that enables video ads to be served across all compliant video players. However, VAST alone does not provide support for rich interactivity. VAST alone only supports relatively simple in-stream video ad formats that are not executable. These simple ad formats do not provide an interactive user experience, and do not allow the advertiser to collect rich interaction details.

Layering VPAID onto VAST offers an enhanced solution. VPAID establishes a common communication protocol between video players and ad units that allows a single “executable ad” (one that requires software logic to be executed as part of ad playback) to be displayed in-stream with the publisher’s video content, in any compliant video player. Furthermore, it enables the executable ad unit to expect and rely upon a common set of functionality from the video player. VPAID enables the video player to expect and rely upon a common set of functionality from the executable ad unit. The significance is that advertisers using VPAID ads can provide rich ad experiences for viewers and collect ad playback and interaction details that are just as rich as the ad experience. With the adoption of VPAID, advertisers have more control over the display experience in their video campaigns. Also, as VPAID compliant video players enable a more diverse and interactive set of video advertising, VPAID compliant publishers should expect to sell more instream video inventory. With VPAID, the IAB aims to address the following market inefficiencies for publishers, advertisers, and vendors by:

  • Increasing common video ad supply technology so that video publishers can readily accept video ad serving from agency ad servers and networks;
  • Providing common technology specifications for advertisers to develop against, thereby decreasing the cost of creative production and thus increasing business ROI;
  • Improving video ad supply liquidity, thus decreasing the cost of integration with each publisher.

To improve the interactive ad experience in video players, publishers should build their video players to the VPAID specifications outlined in this document. These specifications were defined with creativity and innovation in mind and should not limit video player design. As with all IAB guidelines and specifications, this document will be updated as video advertising progresses and new ad formats become more widely adopted.

Source: IAB