VAST Version
Control which VAST versions are accepted in your ad specification. Advalidation checks every submitted tag and rejects versions that don't match your requirements.
Why VAST version matters
The Video Ad Serving Template (VAST) specification has evolved from version 1.0 to 4.1. Each version introduces capabilities: VAST 2.0 added companion ads and non-linear ads, VAST 3.0 introduced ad pods and skippable ads, and VAST 4.0 brought mezzanine file support and verification resources.
Not all video players support all versions. A VAST 4.1 tag sent to a player that only supports VAST 2.0 may fail silently, display incorrectly, or not play at all. Without version validation, these incompatibilities surface in production as blank ad slots and lost revenue.
How version validation works
When you configure your ad specification, you select which VAST versions to accept. Advalidation parses the VAST XML and checks the version attribute against your allowed versions. Tags that don't match are flagged immediately with a clear fail result showing the declared version.
Common configurations
Most publishers and broadcasters accept a range of versions:
- VAST 2.0 and above: Ensures basic feature support while accepting newer tags
- VAST 3.0 and above: Required for skippable ad support or ad pod handling
- VAST 4.0 and above: Strictest setting, ensures access to verification resources and mezzanine files
Part of VAST tag validation
Version validation is one check in a broader VAST testing workflow. Advalidation also validates media files, detects VPAID usage, identifies creative variations, and flags property discrepancies. See all checks on the video tests page.