VAST
VAST (Video Ad Serving Template) is an XML standard defining how a video player requests an ad from a server and how it should report playback events — start, pause, skip, completed view. It exists so the same video ad can run across different players and platforms without a custom integration for each one.
How VAST works
The player sends a request through a VAST tag, and the ad server returns an XML document with a link to the video file, its duration, skip options, and a set of tracking pixels for playback events. Those pixels are what let a buyer count actual viewing milestones instead of just a raw impression.
VAST in PWA arbitrage
The format matters when a buyer is running video traffic, such as pre-roll or in-stream, to drive users to a PWA offer rather than relying only on push or native ads. The key detail is making sure the post-view conversion event lands in the same tracker as every other channel, or video traffic ends up siloed in its own reports and harder to compare against push and pop on final CPI.
FAQ
- Does a buyer need to build a VAST tag themselves?
- Usually not — the platform or network selling the video inventory already provides a ready VAST tag, and the buyer just needs to wire it into their own tracker correctly. Deep VAST configuration is mostly the ad server's job, not the buyer's.
- How is VAST different from a regular banner format?
- A banner is a static or animated image with a direct click, while VAST describes an entire delivery and reporting protocol built specifically for video, including pauses and viewing milestones. That's why video traffic needs its own tracking setup rather than reusing a banner's.
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