VAST vs VPAID Explained: How they Work, Difference, and Tips

Video advertising is a relatively new and emerging form of digital advertising. Hence it is a common observation that most people are getting confused among the formats of video ads. The Interactive Advertising Bureau is an institution responsible for setting standards and best practices for uniformity around online advertising. IAB coined the specifications: VAST & VPAID in 2008 and 2012, respectively. It was built for publishers to serve third-party ads across multiple platforms or devices with the video player of their choice.

VAST & VPAID Explained

VAST is the acronym for Video Ad Serving Template. It was designed to facilitate communication between different video players and ad servers so that all types of video ads would comply with every video player. VAST uses an XML script to give the video player specific instructions for serving the ad, such as which ad creative should play, whether or not it is skippable and where to find the original file, how it should show up in the player, how long it should be displayed for. VAST removes the cost and time associated with custom-coding in-stream video ads by establishing a universal, standard connection between video players and ad units. So, it not only benefits advertisers by ensuring that all their video ads run smoothly on all video players but also benefits publishers by creating more monetizable demand. 

There are several versions of VAST.  VAST 1.0 supports MP4, 3GP, .MOV, play/stop/pause functionality, and basic event tracking. VAST 2.0 supports MP4, 3GP, .MOV, Flash, JavaScript, play/stop/pause functionality, quartile event and player tracking (linear, non-linear, and companion ads). VAST 3.0 supporting five ad formats, skippable ads, OBA compliance, and improved error reporting. VAST 4.0 supports separate video and interactive files, mezzanine files, server stitching, viewability, verification, and advanced reporting. After all developments and upgrades, VAST is currently running at 4.1 for all users.

VPAID stands for Video Player Ad-Serving Interface Definition. It was introduced to establish a more advanced common interface that supports rich interactivity. The rich media ad units are also called executable ad units ads, which provide an interactive user experience and collect essential data on the interaction metrics. A VPAID code running within a video player can record if a user clicks on an overlay, plays and pauses the content, or closes the in-stream ad. These performance insights give advertisers the ability to measure individual ads’ effectiveness, which can then be improved for better interactivity. VPAID has had two versions: VPAID 1.0 and VPAID 2.0. VPAID 1.0 supports ad rendering on desktop and limited functionality with Flash. The latest version VPAID 2.0, supports ad rendering on mobile devices, autoplay VPAID on chrome for players smaller than 400×300, more comprehensive range of functionality than Flash using HTML5 and JS.

How do They work?


  • Calling for a request is the initial stage where the video players call or ping the ad server requesting to fetch an ad.
  • Making a response is the next call where the ad server responds to the video player containing the media files and needs tracking URLs.
  • Triggering the URLs is the final stage where the video player launches the tracking URLs or pixels to allow third parties to start tracking and measuring impressions.


  • Here, the first step is also Calling for a request, where the video player requests an ad call from the ad server.
  • The next step of Making a response, where the ad server responds to the video player having the VAST XML file and the VPAID compliant ad unit or executable ad units.
  • Communicating throughout is the intermediate step where the video player and video ad unit constantly exchange properties and events to-and-fro between them.
  • The final stage of Tracking activities is where both the video player and video ad unit send the tracked impressions and other activity data to their respective ad servers.

The rapid growth of interactive ad usage and the response of the viewers seem to coincide accordingly. Overall engagement for interactive video ads is almost six times the results of standard ads, and the latter lag behind interactive ads across all crucial metrics. In this booming era of content, interactive ads’ varied formats, styles, and engagement opportunities have proven increasingly attractive.

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