Compare Messages - Pidgeon Health

POST /api/diff

Compare two messages and return field-level differences. Diff is a Post Pro feature. The Bridge route is unauthenticated because the Bridge is a single-user loopback sidecar; the Pro entitlement is enforced in the app, not on the loopback route.

Request Body

Field	Type	Default	Description
`leftMessage`	string	Required	Baseline message
`rightMessage`	string	Required	Comparison message
`standard`	string	Auto-detect	`hl7`, `fhir`, `ncpdp`
`ignoredFields`	string[]	`[]`	Fields to exclude (e.g., `["PID.3", "MSH.10"]`)

Example

curl

curl -X POST http://localhost:5101/api/diff \
  -H "Content-Type: application/json" \
  -d '{
    "leftMessage": "MSH|^~\\&|SENDER|FAC|RECV|DEST|20260222||ADT^A01|12345|P|2.3\rPID|1||MRN001^^^MRN||DOE^JOHN||19800101|M",
    "rightMessage": "MSH|^~\\&|SENDER|FAC|RECV|DEST|20260222||ADT^A01|12345|P|2.3\rPID|1||MRN001^^^MRN||DOE^JANE||19800101|F",
    "standard": "hl7",
    "ignoredFields": ["MSH.10"]
  }'

Response

{
  "success": true,
  "data": {
    "differences": [
      {
        "field": "PID.5.1",
        "leftValue": "JOHN",
        "rightValue": "JANE",
        "changeType": "modified"
      },
      {
        "field": "PID.8",
        "leftValue": "M",
        "rightValue": "F",
        "changeType": "modified"
      }
    ],
    "totalDifferences": 2,
    "ignoredFields": ["MSH.10"]
  },
  "error": null
}