VAST Tag Validator
Use this tool to validate your VAST tags by entering a VAST tag URL or VAST XML content. The validator will analyze the structure of your VAST XML, check for common errors, and provide insights to help you debug any issues.
Other Ad Validators
IAB Standards Guardrails
Run smarter VAST audits that understand which version you are targeting and flag unsupported elements before ad servers reject your campaigns.
Go beyond basic Ad previews
Create a free account to access advanced test features and save your test history
IAB valid XML every time
How the version-aware guardrail works
- AdMeIn inspects the <VAST version="x.x"> attribute and fetches the XML produced by your audit.
- Each node and attribute is compared with our library of IAB schema changes across VAST 2.0–4.2.
- Unsupported items are flagged with the version where they became valid and a remediation note.
- You can open the dedicated IAB Standards page in your dashboard to explore the interactive tree and summaries.
Real-world failures we highlight
This element is ignored when your ad declares version 3.0 or lower. Update the version or strip the node.
Bitrate exceeds the IAB recommended maximum and may affect certain SSAI workflows.
OMID events require VAST 4.1+ and a valid <AdVerifications> block.
Version coverage matrix
What passes: Linear creatives, basic TrackingEvents, simple CompanionAds
What fails: AdVerifications, UniversalAdId, Mezzanine, OMID events
What passes: Clickable icons, nonlinear companions, error tracking
What fails: Mezzanine, AdVerifications, AdServingId updates
What passes: Mezzanine hierarchy, mezz/stream bitrate rules, AdVerifications
What fails: Legacy companion required attributes, unsupported Flash MIME types
Built into your existing workflow
Inspect the interactive tree to see which parent node introduced an unsupported element.
See what elements are failing and why without needing to cross-reference the IAB documentation or test in an ad server first.
Re-run `iab-standards` validation after edits with a single click to confirm the fix.
Key Features
- Version-aware compliance for VAST 2.0 through 4.2
- Highlights unsupported nodes and attributes with root-cause explanations
- Side-by-side comparison of what each VAST spec allows vs. your XML
- Companion summaries and interactive tree to inspect failures quickly
- One-click revalidation after editing your XML
Go beyond basic Ad previews and Turn Ad testing into real insights
Creating an account allows you to unlock additional features such as saving your test history, accessing advanced validation reports, and receiving personalized support. Enhance your ad testing experience and streamline your workflow by signing up today!
Sign up in seconds
It’s free — no credit card required
See pricing options for subscription options.
Sign-up now to get access to AdMeIn full test suites
- Save and access your test history anytime
- Get detailed validation reports
- Access advanced testing features
- Access to premium validation features
- Priority features and updates
- Clean dashboard without ads and clutter