Nexxen VAST validator guide
Short answer: Nexxen's standard video specs ask for a progressive MP4 in H.264, preferably 1920×1080 or 1280×720, with several CTV bitrates and SSL on every ad. VPAID is not accepted on CTV. The same page does not publish a VAST version matrix, so validate the tag XML on its own and then check the media files against this spec.
Need a Nexxen VAST validator?
Validate the XML first, then compare each MediaFile with the desktop and CTV rows below.
Quick reference
| File | Progressive MP4, H.264, de-interlaced |
| Frame size | 1920×1080 or 1280×720 preferred |
| Aspect ratio | Desktop, mobile, and tablet: 16:9 or 4:3. CTV: 16:9. |
| Duration | 30 seconds maximum. Listed lengths are 6, 15, and 30 seconds, and under 30 seconds is recommended. |
| File size | Desktop, mobile, and tablet up to 30 MB. CTV source file 5 MB minimum and 30 MB maximum. |
| Video bitrate | 800–1,024 kbps or higher. CTV: multiple files from 1,000–5,000 kbps. |
| Audio | 64–128 kbps at 44.1 kHz or higher |
| Frame rate | 23.976 or 29.97 fps |
| Streaming protocols | HLS in the US, MPEG-DASH in the EU |
| VPAID | Not accepted on CTV. The deliverable line says VAST. |
| Transport | SSL required on every ad |
Desktop and CTV are different rows
The specs page covers branded video on desktop, connected TV, smartphones, and tablets, and then splits several rows. A single 4:3 file can fit desktop, mobile, or tablet and still miss the CTV aspect ratio. A single mid-bitrate MP4 can meet the general line of 800 kbps or higher and still miss the CTV request for multiple renditions between 1,000 and 5,000 kbps.
Put those renditions in the VAST MediaFiles set: progressive delivery, type="video/mp4", and width, height, and bitrate filled in so a player can choose. Nexxen also names HLS in the US and MPEG-DASH in the EU as streaming protocols. If the tag only carries one progressive MP4, confirm with the placement whether that protocol row is required for the buy.
VPAID and SSL
Nexxen states the CTV rule twice: deliver VAST, and VPAID is not accepted on CTV. A tag whose only media file uses apiFramework="VPAID" will fail that check even when the XML is otherwise well formed. See the VPAID deprecation note before reusing an older interactive creative.
The guidelines also say every ad needs to be SSL-compliant, and that autoplay audio is prohibited. Autoplay video is allowed when the audio stays muted until the viewer turns it on. In the tag, that means media, impression, tracking, and wrapper URLs all use HTTPS.
CTV controls listed on the page are play, pause, and mute. A volume control that can reach zero may stand in for mute. Those are player controls, so they will not appear as elements in the VAST XML.
Pre-flight checklist
- The tag is VAST, and CTV placements do not depend on VPAID.
- At least one progressive H.264 MP4 is 1920×1080 or 1280×720.
- CTV tags include 16:9 renditions across 1,000–5,000 kbps.
- Duration is 6, 15, or 30 seconds, and not longer than 30 seconds.
- Every URL in the tag is HTTPS.
- The resolved XML passes the validator.
What the specs page leaves open
Nexxen publishes the creative file and the CTV VPAID ban. It does not publish a VAST version list or a wrapper hop limit on this page. A tag can match the file spec and still fail in a downstream player that caps wrapper depth. Resolve the chain in the inspector when the Nexxen creative is reached through another ad server.