vastlint
VAST-2.0-text-only-element

VAST-2.0-text-only-element

Text-only element contains a child element

ErrorSchemaIAB VAST 2.0 §2VAST 2.0 and later (all versions)

Short answer

Elements like <AdTitle>, <AdSystem>, <Duration>, and <Impression> are defined in the VAST schema as text-only (they may only contain text or CDATA, not child elements). A child element inside one is a schema violation.

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. Schema violations tend to create parser disagreement. One system may recover while another drops the tag entirely, which is why these bugs often show up as environment-specific fill loss. Affected scope: VAST 2.0 and later (all versions).

How to fix

Remove the child element — text-only elements such as <AdTitle>, <Duration>, and <Impression> accept only text or CDATA content.

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Other Schema rules

VAST-2.0-unknown-attributeElement has an attribute not defined in the VAST specVAST-2.0-inline-unknown-child<InLine> contains an unrecognised child elementVAST-2.0-wrapper-unknown-child<Wrapper> contains an unrecognised child elementVAST-2.0-creatives-unknown-child<Creatives> may only contain <Creative> elementsVAST-2.0-creative-unknown-child<Creative> contains an unrecognised child elementVAST-2.0-linear-unknown-child<Linear> contains an unrecognised child elementVAST-2.0-trackingevents-unknown-child<TrackingEvents> may only contain <Tracking> elementsVAST-2.0-mediafiles-unknown-child<MediaFiles> contains an unrecognised child element