VAST tracking events / NonLinear
adExpand VAST tracking event
Short answer: Fires when the creative expands. 4.0+ name replacing expand. Introduced in VAST 4.0.
When it fires
The creative itself expanded (an overlay growing, not the player). Use adExpand on VAST 4.0 and later. expand was removed.
The creative expanded
adExpand fires when the NonLinear creative itself grows. VAST 4.0 introduced it to replace expand, so the creative would not share a name with the player surface. playerExpand is that other event, and it is linear.
A 3.0 player will not call adExpand. Keep expand on a 3.0 document. A 4.x document that still says expand records the expansion in the UI and not in the beacon.
Expansion that is a click and expansion that is not
Some overlays expand on hover or on a timer and never navigate. adExpand fires. ClickThrough does not. An engagement rate built only from clicks misses those. Some overlays navigate immediately and never resize. The click fires and adExpand does not. Pick the event that matches the creative you shipped.
A 4.x document that lists expand and adExpand gets the call on adExpand. The old element is inert. It does not cause the new one to fail. It does waste a reviewer's time, because the file looks like it measures expansion twice.
When the column stays empty
adExpand is absent from VAST 2.0 and from 3.0. A player that only implements those versions will not request it. The version table on this page is the set that includes it.
Each wrapper hop may include its own adExpand URL. The player requests every one of them when the event happens, so a chain of four hops produces four calls for one playback. An http URL on an https page is dropped by the browser before the ad server sees a miss. The event name can be right and the scheme can still zero the column.
Where it is valid
| 2.0 | 3.0 | 4.0 | 4.1+ |
|---|---|---|---|
| No | No | Yes | Yes |
Legal containers: NonLinear. An event in the wrong container is not a player error. It is a URL nobody calls.
Using it in a tag
Put it in a NonLinear TrackingEvents block. It is not valid on the other creative types, and a player does not fire a tracker in the wrong container.
<NonLinear>
<TrackingEvents>
<Tracking event="adExpand">
<![CDATA[https://track.example.com/adExpand]]>
</Tracking>
</TrackingEvents>
</NonLinear>VAST XML fragment only. This excerpt belongs inside a complete VAST document, so standalone validation will fail until it is wrapped in a full <VAST>response.
Related vastlint rules
- VAST-4.0-tracking-event-removed: fullscreen/exitFullscreen tracking events were removed in VAST 4.0
- VAST-4.1-tracking-event-value: Tracking event attribute not in the valid set for this VAST version
Related events
- expand: Removed in VAST 4.0. Use adExpand on 4.x tags.
- adCollapse: Fires when the creative collapses after expand. 4.0+ name.
- playerExpand: Fires when the player grows (4.0+ replacement for fullscreen).
Check the XML, then confirm the beacons fire
Validate the event names and containers on the document. Test a live URL when the XML is clean and reporting is still empty.