vastlint

VAST XML Validator & Tag Tester

Drop a .xml file, paste a VAST tag, or type XML below. Validates against IAB VAST 2.0–4.3. Results appear instantly, nothing is stored.

Want to test a VAST URL and preview the creative? Try the VAST Tag Tester →

Drop a .xml file or URL · paste XML or a URL · auto-validates · ⌘↵ to validate now

118

rules

6

VAST versions

<1ms

validation

0

data stored

WebCLIVS CodeREST APIRustGonpm

How it works

  • → Validates against IAB VAST 2.0, 3.0, 4.0, 4.1, 4.2, and 4.3 specs. Version is detected automatically from the version attribute.
  • → Checks for missing required fields, malformed URLs, empty elements, deprecated features, VPAID, version mismatches, and more.
  • → Your XML is never stored. The validation response is returned immediately and discarded.
  • → Want validation in CI/CD? Use the vastlint CLI brew install aleksUIX/tap/vastlint
  • → Need a REST API? vastlint is on RapidAPI: validate VAST tags with a single HTTP call. Subscribe free →