VAST (Video Ad Serving Template) is the IAB standard that governs how video ads are delivered to CTV devices. When a CTV player needs to show an ad, it calls the ad server, which returns a VAST XML file containing: the video file URL, duration, click-through URL, and tracking pixel URLs (impression, quartile events, complete).
Key VAST facts for India CTV buyers:
- SSAI and VAST: JioCinema and Hotstar use server-side ad insertion (SSAI) — the ad is stitched into the content stream server-side. This means client-side VAST tracking pixels do not fire. Third-party verification (IAS, DoubleVerify) cannot measure these platforms via standard VAST pixel methods.
- VAST chains: If your campaign runs through multiple ad servers (agency, DSP, advertiser), each is a VAST wrapper redirect. Keep chains to 2 hops or fewer — longer chains cause timeouts on India CTV platforms (2–3 second timeout threshold).
- VPAID is retiring on CTV: VPAID (JavaScript-wrapped interactive ads) does not work reliably on native CTV apps and has security issues. Use VAST only for CTV. Interactive CTV uses SIMID (the replacement standard).
- VAST version: Confirm platform VAST version support before trafficking. Most India platforms support VAST 2.0 or 3.0.
Full guide
For a complete explanation, read: VAST and VPAID on CTV: the video ad standards every buyer needs to understand