VAST Ad Validator · For Ad Ops & Publishers

Validate VAST tags before they go live

Resolve multi-level wrapper chains, validate XML schemas against VAST 2.0–4.x standards, inspect media files for technical compliance, and preview creatives — all saved as persistent project reports.

VAST 2–4.x
schema coverage
∞ hops
wrapper chains
Persistent
saved reports
How it works

From VAST URL to validated report in seconds

No configuration required. Paste a URL and get a complete audit.

1

Paste URL or upload XML

Drop in a VAST tag URL or paste raw XML. We handle both inline VAST and multi-level wrapper redirects — no configuration needed.

2

We audit everything

Wrapper chains are resolved hop by hop, XML is validated against the schema, and media files are inspected for resolution, bitrate, codec, and duration.

3

Review your report

A persistent, revisitable report with every finding — schema errors, warnings, media specs, and a live preview of the creative.

Capabilities

Everything you need to ship clean VAST

A complete audit suite for ad ops teams, publishers, and anyone managing VAST tags at scale.

Wrapper chain resolution

Follows every redirect hop until reaching the inline VAST, mapping the full chain and flagging broken or circular links.

XML schema validation

Validates document structure against VAST 2.0, 3.0, and 4.x specifications, reporting every violation with context.

Media file analysis

Inspects video codec, bitrate, resolution, and duration — surfacing compliance issues before the tag goes into rotation.

Creative preview

Plays the ad creative directly in the validator so you can confirm it renders correctly before signing off.

Persistent project reports

Every validation run is saved to your workspace. Revisit or compare reports at any time.

Errors & warnings breakdown

Every issue is categorised by severity — errors that block delivery, warnings to review, and informational findings.

Debugging a specific error code? Browse the VAST error codes reference — every code from 100 to 902 with causes and fixes.

Coming next · Tag Monitoring

Know when your VAST tag breaks — before your revenue does

We're building continuous monitoring on top of the validator: scheduled re-checks of your tags, latency and availability history, and instant alerts when a tag stops returning valid VAST or a media file goes bad.

Early access

Get early access to VAST tag monitoring

Drop your email and we'll let you know when monitoring opens up — and ask what you'd want alerted on first.

Free — no signup to validate

Check your first tag in thirty seconds

Paste a VAST tag URL or the raw XML and get the full audit — wrapper chain, schema, and every media file probed. No account, no API key, no card.

Used by ad ops teams checking tags across Google Ad Manager, FreeWheel and Extreme Reach.