vastlint

VAST XML Validator

Drop a .xml file, paste a VAST tag, or type XML below. Results appear instantly — nothing is stored.

Drag & drop a .xml file · paste · or type, then ⌘↵

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