Example 3 · API Framework Orchestration

New field, existing service — configuration only

The bank's core team adds overdraftLimit to the existing balance middleware. Audax exposes the new field through the canonical layer and out to every channel with a one-line change to the egress mapping config — no code, no redeployment.

Steps 1–3 are identical in both states. Only the canonical response (step 4) and the rendered external response (step 5) gain the new field — and only because a single line was added to the egress mapping.

identifier lookup
The bank's core team has added a new <OverdraftLimit> field to the middleware response. The canonical schema now surfaces it as overdraftLimit — produced by a single new line in the egress mapping config. No transformation code was changed.
```
GET /customer/v2/customers/{profileId}/accounts/{accountToken}

{
  "profileId": "PTR0000000001",
  "accountId": "02000103664-121-ID-IDR-1",
  "accountNumber": "70000600503",
  "accountCurrency": "IDR",
  "accountStatus": "Active",
  "balance": {
    "availableBalance": 1000,
    "ledgerBalance": 2000
  },
  "overdraftLimit": 500
}
```