vastlint
VAST-2.0-wrapper-vastadtaguri

Wrapper must contain VASTAdTagURI

<Wrapper> must contain <VASTAdTagURI>

ErrorRequired fieldsIAB VAST 2.0 §2.5VAST 2.0 and later (all versions)

Short answer

A wrapper without <VASTAdTagURI> has no next-hop URL to fetch, so the wrapper chain stops immediately and the ad cannot resolve.

`<VASTAdTagURI>` is the URL the player must fetch to retrieve the next VAST response in the wrapper chain. Without it the wrapper cannot be resolved.

Why this matters in production

This rule is usually a delivery blocker. Many players, SDKs, and ad servers will discard the response or skip the affected creative once this condition is hit. Required-field failures usually stop validation early because the platform cannot determine the basic shape of the ad, the creative metadata, or the mandatory tracking payload. Affected scope: VAST 2.0 and later (all versions).

How to fix

Add <VASTAdTagURI><![CDATA[https://next-adserver.example.com/vast.xml]]></VASTAdTagURI> inside <Wrapper>.

Invalid

<Wrapper>
  <Impression><![CDATA[https://tracker.example.com/wrapper-impression]]></Impression>
  <!-- missing VASTAdTagURI -->
  <Creatives></Creatives>
</Wrapper>

Valid

<Wrapper>
  <VASTAdTagURI><![CDATA[https://ads.example.com/next-hop.xml]]></VASTAdTagURI>
  <Impression><![CDATA[https://tracker.example.com/wrapper-impression]]></Impression>
  <Creatives></Creatives>
</Wrapper>
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Other Required fields rules

VAST-2.0-root-elementRoot element must be <VAST>VAST-2.0-root-version<VAST> must have a version attributeVAST-2.0-root-version-valueVAST version attribute must be a recognised version stringVAST-2.0-root-has-ad-or-error<VAST> must contain at least one <Ad> or <Error>VAST-4.0-wrapper-root-error<VAST> root contains both <Ad> and <Error> elements (invalid per VAST 4.0)VAST-2.0-ad-has-inline-or-wrapperEach <Ad> must contain exactly one <InLine> or <Wrapper>VAST-2.0-inline-adsystem<InLine> must contain <AdSystem>VAST-2.0-inline-adtitle<InLine> must contain <AdTitle>