---
type: "datatype"
title: "canonical"
datatype: "canonical"
---
# canonical

- [Datatypes](/datatypes)
- [Definitions](/datatypes-definitions#canonical)
- [Examples](/datatypes-examples#canonical)
- [Mappings](/datatypes-mappings#canonical)
- [Profiles](/datatypes-profiles#canonical)

## Primitive Details
- **Definition**: A URI that is a reference to a canonical URL on a FHIR resource
- **Comments**: see [Canonical References](references.html#canonical)
- **XML Schema/Base**: `xs:anyURI+`
- **JSON Type**: `string`
- **Regex**: `\S*`