Amazon DSP Turns On VAST 4 for Third-Party Publisher Video Inventory Across 34 Countries — Amazon-Operated Surfaces Like Fire TV and Stores Stay on VAST 2/3 With No Upgrade Timeline
PPC Land reported on September 2, 2026 that Amazon DSP now supports VAST 4.0 through 4.3 on third-party publisher video inventory in 34 countries. The platform negotiates the highest compatible version per impression, so publishers still running VAST 2/3 keep receiving those versions and nothing breaks. There is no transition deadline and no required advertiser action — managed-service and self-service buyers get the capability automatically. The practical unlock is for agencies and brands running their own advertiser ad servers, who can now serve VAST 4 tags on Amazon DSP third-party inventory instead of downgrading their creative. The notable limitation is that Amazon-operated properties, including Fire TV and Amazon Stores, continue to accept only VAST 2/3 creatives, and no timeline or explanation was given for that split.
Real-World Impact
The support covers 34 countries and four VAST revisions (4.0 through 4.3). For a campaign mixing Amazon-owned and third-party supply, that still means maintaining two creative specifications — a VAST 2/3 asset for Fire TV and Amazon Stores placements and a VAST 4 asset for the third-party pool — because no timeline was given for aligning the two.
Key Points
- Reported September 2, 2026 — Amazon DSP supports VAST 4.0, 4.1, 4.2 and 4.3 on third-party publisher video supply
- Live in 34 countries: US, Canada, Mexico and Brazil in the Americas; Germany, Spain, France, Italy, UK, Belgium, Switzerland, Poland, Turkey, Austria, Netherlands, Sweden, Finland, Norway, Ireland, Denmark and Luxembourg in Europe; Saudi Arabia, UAE, Israel, Egypt, Morocco, Bahrain and Kuwait in the Middle East; Australia, India, Japan, China, New Zealand and Singapore in Asia Pacific
- Version negotiation is automatic and per impression — Amazon DSP serves the highest version the publisher supports, and publishers on VAST 2/3 continue to receive VAST 2/3
- No advertiser action is required and no transition deadline was announced; both managed-service and self-service buyers get access automatically
- The capability that matters for agencies: those running proprietary or third-party advertiser ad servers can now deploy VAST 4 tags on Amazon DSP third-party inventory instead of downgrading creatives
- VAST 4 features available on that supply include mezzanine source files separated from renditions (supporting server-side transcoding), registered universal advertisement identifiers for frequency capping and reconciliation, Open Measurement verification signals, SIMID interactive playback, and wrapper redirect limits
- Amazon-operated inventory — the report names Amazon Stores and Fire TV — continues to only support VAST 2/3 creatives, with no upgrade timeline and no explanation given
- That split means a single Amazon DSP campaign can require two creative specifications depending on whether the impression lands on Amazon-owned or third-party supply
- The announcement provided no figures on how much supply was previously unreachable, publisher adoption rates, or the share of impressions affected by version negotiation
What You Should Do Now
- 1If you traffic Amazon DSP video through your own ad server, stop downgrading tags to VAST 2/3 for third-party line items and test a VAST 4 tag on a small flight
- 2Keep a VAST 2/3 fallback creative in rotation for Amazon-owned inventory such as Fire TV and Amazon Stores, since those surfaces have no announced upgrade path
- 3Check whether Open Measurement verification and universal ad identifiers now report on your third-party Amazon DSP supply, since those signals were unavailable on tags that previously had to be downgraded