When a Bundle of resources is returned by the FHIR server, Vanya automatically validates each resource against the FHIR R4 specification. If any non-conforming resources are found, yellow validation errors and warnings are displayed. Validation can be switched on or off by toggling the “Check Conformance” checkbox on the Vanya toolbar.

Warnings of non-conforming resources appear in three places, demonstrated by the above example taken from Procedure resources on the HAPI test server. As the HAPI server is a public server used by various developers and students, non-conforming data is quite common. If you encounter conformance errors when viewing data on your own FHIR server, you should take it seriously and fix the underlying data issues.

- Warning message
“4 resources contain conformance issues. Click on the resource for more information.” If any non-conforming resources are found, the number of resources affected will be included in the warning message at the top of the screen. In this example, 4 resources are affected.

- Warning icon
The yellow warning icon next to the four individual resources in the grid draws attention to the specific resources that are affected. Clicking on each of these in turn populates the detailed view to the right of the screen with the precise conformance issue detected.

- Error details
The errors found in the example point to a missing “subject” element, which has a cardinality of 1 in the FHIR R4 specification, making it a mandatory field. “Element: subject: Element 'subject' with minimum cardinality 1 cannot be null”