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JSON Input

FUME evaluates mappings against JSON. When contentType is application/json, application/fhir+json, or text/json, the input is already in the shape that the engine evaluates.

Inspect normalized JSON​

Use the root endpoint with fume: "$" when you want to confirm the exact JSON value the engine sees.

{
  "input": [{ "encounterId": "enc-1001" }],
  "contentType": "application/json",
  "fume": "$"
}

For JSON requests, input is a JSON value rather than a string.

Original input file​

Canonical JSON input

This file is evaluated as-is because JSON input does not go through a format-conversion step.

JSON
[
  {
    "encounterId": "enc-1001",
    "patientId": "pat-0001",
    "status": "finished",
    "class": "outpatient",
    "type": "primary-care",
    "reason": "routine follow-up",
    "facility": "ExampleCare Clinic",
    "practitionerId": "prac-4001",
    "start": "2026-02-14T09:30:00Z",
    "end": "2026-02-14T10:05:00Z"
  },
  {
    "encounterId": "enc-1002",
    "patientId": "pat-0001",
    "status": "finished",
    "class": "outpatient",
    "type": "imaging",
    "reason": "headache evaluation",
    "facility": "ExampleCare Imaging",
    "practitionerId": "prac-4002",
    "start": "2026-03-01T15:10:00Z",
    "end": "2026-03-01T15:45:00Z"
  },
  {
    "encounterId": "enc-1003",
    "patientId": "pat-0001",
    "status": "in-progress",
    "class": "virtual",
    "type": "care-coordination",
    "reason": "medication questions",
    "facility": "ExampleCare Clinic",
    "practitionerId": "prac-4003",
    "start": "2026-03-10T11:20:00Z",
    "end": ""
  },
  {
    "encounterId": "enc-1004",
    "patientId": "pat-0001",
    "status": "planned",
    "class": "outpatient",
    "type": "lab",
    "reason": "fasting labs",
    "facility": "ExampleCare Clinic",
    "practitionerId": "prac-4001",
    "start": "2026-03-20T08:00:00Z",
    "end": ""
  }
]

Normalized JSON before evaluation​

Normalized JSON

The normalized result is identical to the original JSON input.

[
  {
    "encounterId": "enc-1001",
    "patientId": "pat-0001",
    "status": "finished",
    "class": "outpatient",
    "type": "primary-care",
    "reason": "routine follow-up",
    "facility": "ExampleCare Clinic",
    "practitionerId": "prac-4001",
    "start": "2026-02-14T09:30:00Z",
    "end": "2026-02-14T10:05:00Z"
  },
  {
    "encounterId": "enc-1002",
    "patientId": "pat-0001",
    "status": "finished",
    "class": "outpatient",
    "type": "imaging",
    "reason": "headache evaluation",
    "facility": "ExampleCare Imaging",
    "practitionerId": "prac-4002",
    "start": "2026-03-01T15:10:00Z",
    "end": "2026-03-01T15:45:00Z"
  },
  {
    "encounterId": "enc-1003",
    "patientId": "pat-0001",
    "status": "in-progress",
    "class": "virtual",
    "type": "care-coordination",
    "reason": "medication questions",
    "facility": "ExampleCare Clinic",
    "practitionerId": "prac-4003",
    "start": "2026-03-10T11:20:00Z",
    "end": ""
  },
  {
    "encounterId": "enc-1004",
    "patientId": "pat-0001",
    "status": "planned",
    "class": "outpatient",
    "type": "lab",
    "reason": "fasting labs",
    "facility": "ExampleCare Clinic",
    "practitionerId": "prac-4001",
    "start": "2026-03-20T08:00:00Z",
    "end": ""
  }
]

What to expect​

  • Arrays, objects, numbers, booleans, strings, and null keep their JSON types.
  • A mapping that works against this JSON works the same way when you send the original JSON request body, because no extra normalization step changes the structure first.