VAST Tag Validator

Validate and inspect VAST responses online. Check VAST XML and investigate common problems with video advertising tags before they are deployed.

VAST testing vs VAST validation

While VAST testing focuses on rendering the video ad and ensuring it plays correctly in a player, VAST validation focuses on inspecting the underlying XML structure. The validator checks if the VAST response is well-formed, contains the necessary elements, and follows the expected structure, which helps identify why an ad might not be working as intended.

How to validate VAST XML

Paste your VAST URL or the raw VAST XML into the tool above. The application will attempt to parse the structure, retrieve the media files, and extract tracking pixels. If the XML is malformed, you will be able to investigate the structure and find the missing or broken nodes.

Common configuration problems

Many video ad issues stem from simple XML errors. A missing closing tag, an empty MediaFiles section, or incorrectly formatted tracking URLs can cause a creative to fail. Use this tool to verify that your VAST tag provides the essential information required by the video player.

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