VAST-2.0-mediafile-type
VAST-2.0-mediafile-type
<MediaFile> must have a type attribute
ErrorRequired fieldsIAB VAST 2.0 §2.4.1VAST 2.0 and later (all versions)
Short answer
The type attribute on <MediaFile> carries the MIME type of the media (e.g., video/mp4). Players use it to determine whether they can decode the file before fetching it.
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 type="video/mp4" (or the correct MIME type for the video) to <MediaFile>.
Check your VAST tag for
VAST-2.0-mediafile-type and other issues instantly.Open the VAST tag validator →Other Required fields rules
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