Proposed metric has no type
OpenRTB requires Metric.type. Without it, whoever receives the mutated request cannot interpret the value.
What it means
A metric in the metrics payload carries no type. In OpenRTB the Metric object's type names what is being measured, for example viewability, and the value is meaningless without it.
Why it matters
The metric is written into the bid request and travels onward to bidders, which read type first. A typeless metric is a number with no unit, and the request that carries it is no longer valid OpenRTB.
How to fix it
Set type on every metric, and set vendor too when the value did not come from the exchange itself.
Example that trips it
{ "intent": "ADD_METRICS", "op": "OPERATION_ADD", "path": "/imp/imp-1", "metrics": { "metric": [{ "value": 0.82 }] } }Check your payload
Paste a bid request or response into the tester to see whether this code fires against it, or gate on the id in CI with the CLI: the id is stable, wording is not.
Back to the full diagnostic code reference.