vastlint
VAST-4.1-adtype-value

VAST-4.1-adtype-value

Ad adType must be video, audio, or hybrid

WarningValuesIAB VAST 4.1 §2.2.1VAST 4.1, 4.2, and 4.3

Short answer

The adType attribute on <Ad> (VAST 4.1+) must be one of video, audio, or hybrid. Other values are not defined in the spec.

Why this matters in production

This rule is a strong risk signal. Tags with this issue often still parse, but they become brittle across SDKs, SSAI resolvers, and CTV environments. Value-format rules tend to fail at the moment a player interprets a field such as duration, skipoffset, bitrate, or versioning. They are especially painful because the XML can look valid at a glance. Affected scope: VAST 4.1, 4.2, and 4.3.

How to fix

Set the adType attribute on <Ad> to video, audio, or hybrid.

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