---
{
  "title": "FHIR Profiling: FHIRPath Constraints",
  "description": "Constraint - a validation rule that is defined on a profile and described using the FHIRPath syntax.",
  "date": "2025-04-11",
  "author": "Ivan Bagrov",
  "reading-time": "3 min",
  "tags": [
    "FHIR Profiling",
    "FHIR Standard"
  ]
}
---
## FHIRPath Constraints

Constraint - a validation rule that is defined on a profile and described using the [FHIRPath syntax](https://hl7.org/fhirpath/N1/).

Constraints allow for describing more complex data requirements. 

Example of a [profile](https://www.health-samurai.io/articles/fhir-profiling) with a constraint:


```javascript
resourceType: StructureDefinition
url: http://example.org/fhir/StructureDefinition/patient-profile
name: patient-profile
derivation: constraint
type: Patient
status: active
kind: resource
abstract: false
differential:
  element:
	- id: Patient
  	  path: Patient
  	  constraint: 
           - key: patient-data
             severity: error
             human: Patient's name or address are required
             expression: Patient.name.exists() or Patient.address.exists()
```


In this example, a profile with a constraint is described that checks whether the patient must have either a name or an address specified.

Constraints can be specified for the entire resource and for specific complex and primitive types.

Aidbox [FHIR server supports the entire FHIRPath syntax](https://www.health-samurai.io/aidbox).

See also: [FHIR Profiling](/blog/fhir-profiling) and [Unlocking FHIRPath Power](/blog/unlocking-fhirpath-power-a-deep-dive-into-static-type-analysis-for-robust-tooling).