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VAST (Video Ad Serving Template) is the XML response standard published by IAB Tech Lab, defining the ad serving and tracking contract between ad servers and video players. The in-site element skeleton covers 2.0 → 4.4; all data is vendored from the official IAB GitHub repositories and cross-checked.

Data sources & baseline

Official data vendored from the IAB repositories InteractiveAdvertisingBureau/vast.git (commit e0858cd) and InteractiveAdvertisingBureau/VAST4.x.git (commit ccf49aa), fetched on 2026-08-19.

License: THE STANDARDS, THE SPECIFICATIONS, THE MEASUREMENT GUIDELINES, AND ANY OTHER MATERIALS OR SERVICES PROVIDED TO OR USED BY YOU HEREUNDER (THE “PRODUCTS AND SERVICES”) ARE PROVIDED “AS IS” AND “AS AVAILABLE,” AND IAB TECHNOLOGY LABORATORY, INC. (“TECH LAB”) MAKES NO WARRANTY WITH RESPECT TO THE SAME AND HEREBY DISCLAIMS ANY AND ALL EXPRESS, IMPLIED, OR STATUTORY WARRANTIES, INCLUDING, WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AVAILABILITY, ERROR-FREE OR UNINTERRUPTED OPERATION, AND ANY WARRANTIES ARISING FROM A COURSE OF DEALING, COURSE OF PERFORMANCE, OR USAGE OF TRADE. TO THE EXTENT THAT TECH LAB MAY NOT AS A MATTER OF APPLICABLE LAW DISCLAIM ANY IMPLIED WARRANTY, THE SCOPE AND DURATION OF SUCH WARRANTY WILL BE THE MINIMUM PERMITTED UNDER SUCH LAW. THE PRODUCTS AND SERVICES DO NOT CONSTITUTE BUSINESS OR LEGAL ADVICE. TECH LAB DOES NOT WARRANT THAT THE PRODUCTS AND SERVICES PROVIDED TO OR USED BY YOU HEREUNDER SHALL CAUSE YOU AND/OR YOUR PRODUCTS OR SERVICES TO BE IN COMPLIANCE WITH ANY APPLICABLE LAWS, REGULATIONS, OR SELF-REGULATORY FRAMEWORKS, AND YOU ARE SOLELY RESPONSIBLE FOR COMPLIANCE WITH THE SAME, INCLUDING, BUT NOT LIMITED TO, DATA PROTECTION LAWS, SUCH AS THE PERSONAL INFORMATION PROTECTION AND ELECTRONIC DOCUMENTS ACT (CANADA), THE DATA PROTECTION DIRECTIVE (EU), THE E-PRIVACY DIRECTIVE (EU), THE GENERAL DATA PROTECTION REGULATION (EU), AND THE E-PRIVACY REGULATION (EU) AS AND WHEN THEY BECOME EFFECTIVE.

IAB Tech Lab VAST standards page

Version timeline

VAST 4.42024-07CTV Addendum 2024Official XSD cross-checked

CTV Ad Portfolio: NonLinear extended to Pause/Screensaver/Overlay/Squeezeback, standardized QR Code, AdCOM plcmt/pos/playbackmethod/attr signaling

77 elements · 51 attributesBrowse element catalog

VAST 4.32022-12Spec full-text cross-checked

No structural changes: macros moved to GitHub maintenance, [PLAYBACKMETHODS]=7 continuous play, inline data URIs for InteractiveCreativeFile

68 elements · 48 attributesBrowse element catalog

VAST 4.12017-08Official XSD cross-checked

OMID integration (browserOptional), audio ads (adType), AdServingId, Expires, removal of VPAID/Flash

66 elements · 48 attributesBrowse element catalog

VAST 4.02016-01Official XSD cross-checked

Mezzanine files, UniversalAdId, AdVerifications framework, Category, separation of media and interactive files

59 elements · 42 attributesBrowse element catalog

VAST 3.02012-07Official XSD cross-checked

Skippable ads (skipoffset), Ad Pods, Icons, expanded error codes and tracking events

52 elements · 36 attributesBrowse element catalog

VAST 2.02012-03Official XSD cross-checked

Baseline: Linear / NonLinear / Companion and quartile tracking (much legacy traffic still targets this baseline)

37 elements · 17 attributesBrowse element catalog

Element data on this page is generated from the in-site skeleton (data/vast-spec/skeleton/vast.ts); its consistency with official sources is guarded by bidirectional CI cross-checks. Every divergence from the official XSD/spec is registered with factual grounding.