Metric.type

The name of the metric, such as viewability or click-through rate, drawn from a list of names the exchange publishes to its buyers. Required on every Metric.

CurrentstringRequiredSince 2.5

Field facts

Path: imp.metric.type
Object: Metric
Type: string
Requirement: Required
Added: OpenRTB 2.5
Spec section: 3.2.5

How it is used

There is no standard vocabulary. Read the exchange's integration docs for the exact strings it sends and treat unknown names as absent rather than guessing.

Example

Where the field sits in a payload, with everything else left out:

{
  "id": "req-1",
  "imp": [
    {
      "metric": [
        {
          "type": "viewability"
        }
      ]
    }
  ]
}

Common mistakes

Sending free-form names that change between releases breaks every bidder model that keyed on the old string.
Omitting type makes the value meaningless, and the validator reports it as a missing required field.

Version history

Added in OpenRTB 2.5, and present in the latest snapshot. The table shows how each version's spec text types the field.

Versions	Type in the spec	Required	Deprecated
2.5 to 2.6-202606	string	Yes	No