VASTlint
Validate
VAST-4.1-universaladid-content

UniversalAdId needs text content in VAST 4.1+

<UniversalAdId> must have text content in VAST 4.1+

ErrorRequired fieldsIAB VAST 4.1 §2.3.4VAST 4.1, 4.2, and 4.3

Short answer

After idValue was removed, the identifier lives in the element text. <UniversalAdId idRegistry="ad-id.org"></UniversalAdId> is empty and fails this rule.

In VAST 4.1+, the ad identifier is the text content of `<UniversalAdId>`. An empty element means no identifier is present.

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 4.1, 4.2, and 4.3.

How to fix

Place the ad identifier as the text content of <UniversalAdId>, e.g. <UniversalAdId idRegistry="ad-id.org">ADID/2025/001</UniversalAdId>.

Invalid

<UniversalAdId idRegistry="ad-id.org"></UniversalAdId>

Valid

<UniversalAdId idRegistry="ad-id.org">ADID/2025/001234</UniversalAdId>
Check your VAST tag for VAST-4.1-universaladid-content and other issues instantly.Open the VAST tag validator →

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>