An OperationOutcome resource is a FHIR resource type used by a FHIR server to return a message to the consumer. They can contain information messages as well as warning and error messages. Whenever a Bundle of resources is returned, consumers should look for and react to the presence of any OperationOutcome. This is often problematic when using API tools such as Postman, as when a large Bundle of resources is returned by a FHIR server it can be difficult to locate any OperationOutcome resources in the Bundle.

Vanya addresses this is a unique way, by ensuring that any OperationOutcome resources returned appear at the top of the page with appropriate icons determined by the severity of the message.

The screenshots below illustrate two examples of OperationOutcomes returned by two different FHIR servers for two very different reasons. In the first example the Azure test server returned a “warning” OperationOutcome because it truncated the amount of included resources returned. This happened because Azure — and other server providers — sometimes have limits to the number of resources returned in response to _include and _revinclude parameters.

The second example comes from the Firely test server, which returned a “warning” OperationOutcome when it encountered a parameter it was not expecting in the search query. The parameter was deliberately mis-spelled when we ran the query, substituting “_revincluded” for “_revinclude”. In this case, the query still ran, but it ran without using the incorrectly spelled parameter.

Making OperationOutcomes visible in the manner makes it easy for developers and others running search queries to identify problems with their queries or with their data.