Token search is used to search by exact match of codes, Codings, CodeableConcepts, Identifiers...
Modifiers
:of-type
Aidbox (> 2203) support search with of-type modifier for identifiers.
The search parameter has the format system|code|value, where the system and code refer to a Identifier.type.coding.system and .code, and match if any of the type codes match. All 3 parts must be present.
PUT /fhir/Patient/pt1
content-type: text/yaml
resourceType: Patient
identifier:
-value:'value'
type:{coding:[{code:'code',system:'system'}]}
GET /fhir/Patient?identifier:of-type=system|code|value