VAST Inspector
Paste VAST XML or fetch a tag URL (macros like [TIMESTAMP], [CACHEBUSTING] and correlator= are expanded). The inspector follows VASTAdTagURI wrapper hops through the FizzKit relay with per-hop status, latency and size, aggregates impressions and tracking across the chain, and validates the document against the required elements for its version (AdSystem, AdTitle, Impression, Duration, MediaFile, UniversalAdId in 4.0+, AdServingId in 4.1+), skipoffset vs duration, MIME/bitrate/size plausibility, http vs https, duplicate pixels and VPAID deprecation. A ping test fires selected impression, error, quartile, click and verification URLs with [ERRORCODE] of your choice, and the Media tab plays MP4/WebM files inline and HEAD-checks each one. Hand the tag straight to the VAST Ad Tester to run it in Google IMA.
Related tools
VAST Ad Tester (IMA Player)
Play any VAST or VMAP tag in a real Google IMA player and watch every SDK event, error and timing.
VMAP Parser
Fetch or paste VMAP 1.0 manifests — timeline preview, resolve every AdTagURI to VAST, validate, and ping break trackers.
HLS m3u8 Parser
Fetch or paste HLS playlists — drill from master to variants, validate the ladder, HEAD-check segments, decode SCTE-35 cues.
OpenRTB Inspector
Validate & annotate OpenRTB 2.6 BidRequest and BidResponse JSON.
ads.txt / app-ads.txt Validator
Fetch any domain's ads.txt or app-ads.txt, validate it against the IAB 1.1 spec, follow SUBDOMAIN pointers, and cross-check every line against exchange sellers.json files.
How to use VAST Inspector
- 1Paste VAST XML, or enter a tag URL and click Fetch — request macros are expanded for you.
- 2Wrapper hops are followed automatically (max 5); open the Chain tab to see each hop and the aggregated tracking.
- 3Check the Validate tab for errors and warnings, and expand the VAST error-code reference when a player reports a code.
- 4Use the Media tab to play a MediaFile inline or HEAD-check every file, then fire selected pixels from the Ping test tab.
- 5Click "Test in IMA player" to run the same tag in the VAST Ad Tester.
About VAST Inspector
Paste VAST XML or fetch a tag URL (macros like [TIMESTAMP], [CACHEBUSTING] and correlator= are expanded). The inspector follows VASTAdTagURI wrapper hops through the FizzKit relay with per-hop status, latency and size, aggregates impressions and tracking across the chain, and validates the document against the required elements for its version (AdSystem, AdTitle, Impression, Duration, MediaFile, UniversalAdId in 4.0+, AdServingId in 4.1+), skipoffset vs duration, MIME/bitrate/size plausibility, http vs https, duplicate pixels and VPAID deprecation. A ping test fires selected impression, error, quartile, click and verification URLs with [ERRORCODE] of your choice, and the Media tab plays MP4/WebM files inline and HEAD-checks each one. Hand the tag straight to the VAST Ad Tester to run it in Google IMA.
VAST Inspector is part of FizzKit — a collection of focused developer and ad-tech tools. This tool uses the FizzKit relay to fetch public URLs on your behalf (so browser CORS rules do not get in the way); fetched content is returned to your browser and not stored.