Example 4 · API Framework Orchestration

New backend — loan balance (direct REST/JSON integration)

A channel asks: check the customer's loan balance — a brand-new capability, served by a brand-new loan servicing platform the bank has never connected to before. It bypasses the existing core middleware entirely. Audax integrates with it via configuration, because REST/JSON and Bearer auth are already-supported patterns.

identifier lookup
A new canonical endpoint, following the same profileId-scoped, token-based addressing pattern as the account endpoint. Same design, new resource type.
```
GET /customer/v2/customers/{profileId}/loans/{loanToken}/balance

{
  "profileId": "PTR0000000001",
  "loanToken": "a7c2e9f1-...",
  "loanAccountNumber": "LN-2024-008812",
  "loanType": "PERSONAL_LOAN",
  "loanStatus": "Active",
  "balance": {
    "outstandingPrincipal": 45000,
    "nextInstallmentAmount": 1200,
    "currency": "IDR"
  }
}
```
Lua orchestrationLua Orchestration
routes to the new loan servicing platform
request.messageType = "LOAN_BALANCE_INQUIRY" request.profileId = account.profileId route_to("LOAN_SERVICING_PLATFORM")
Egress transformation → loan platform JSONTransformation
canonical request rendered into the loan platform's REST contract — JSON, not XML.
POST https://loan-platform.example/api/v1/loans/balance Authorization: Bearer <service-token> Content-Type: application/json { "loan_ref": "a7c2e9f1-...", "customer_ref": "PTR0000000001" }
Loan servicing platformnew backend — REST/JSON
A new loan servicing platform — separate from the core banking middleware. Exposes its own REST/JSON API.
{ "status": "success", "loan": { "account_number": "LN-2024-008812", "product": "PERSONAL_LOAN", "state": "ACTIVE", "outstanding_balance": 45000, "next_payment": 1200, "currency": "IDR" } }
Response transformationCanonical / Core
Loan platform JSON → canonical shape shown above. Field renames (outstanding_balance → balance.outstandingPrincipal, next_payment → balance.nextInstallmentAmount) and a value mapping (state "ACTIVE" → loanStatus "Active") — same mapping engine as the XML path, applied to JSON instead.
Account balance (Ex 1–3)Loan balance (this example)
BackendCore banking middlewareNew loan servicing platform
Transport / formatHTTP + XMLHTTP + JSON
AuthInternal service authOAuth2 Bearer (already supported)
New connector code?—No — REST/JSON + Bearer already supported