VAST macros / Verification
[REASON] VAST macro
Short answer: Why a verification script was not executed (code 1, 2, or 3). Introduced in VAST 4.1.
What it means
Resolves to the reason code for a verificationNotExecuted event: 1 (could not load), 2 (could not verify), or 3 (rejected). It only has a defined value inside a verificationNotExecuted tracking URI.
Example value
After the player substitutes the macro, [REASON] becomes something like:
2Where it is valid
Only verificationNotExecuted tracking URIs.
Macros are case-sensitive and substituted only inside URL fields. A macro written in the wrong case, or placed where it has no defined value, is sent to the server as literal text instead of a value.
Using it in a tag
<Impression><![CDATA[https://t.example.com/i?val=[REASON]&cb=[CACHEBUSTING]]]></Impression>VAST XML fragment only. This excerpt belongs inside a complete VAST document, so standalone validation will fail until it is wrapped in a full <VAST>response.
Related vastlint rules
- VAST-2.0-macro-unknown: URL contains a [MACRO] that is not a recognised IAB VAST macro
- VAST-2.0-macro-lowercase: Recognised macro is not uppercase — players match macro names case-sensitively
- VAST-2.0-macro-wrong-context: Context-restricted macro ([ERRORCODE]/[REASON]) used where it has no defined value
- VAST-4.1-verification-tracking-reason: verificationNotExecuted tracking URI should include the [REASON] macro
Related macros
- [VERIFICATIONVENDORS]: The verification vendors present in the ad response.
- [OMIDPARTNER]: The Open Measurement partner name and version.
- [ERRORCODE]: The VAST error code for a failure, substituted in Error URIs.
Validate your macros
vastlint flags unknown, mis-cased, deprecated, out-of-context, and unencoded macros in any tracking, click, error, impression, or media URL:
# CLI: exits non-zero on errors, ideal for pipelines
vastlint check creative.xmlUse the right tool for this failure
If you already have the resolved XML, run a pure spec check. If you only have a live tag URL, test that endpoint first. If the failure happens in the wrapper chain, inspect each hop.