{
  "title": "Account Structure",
  "description": "JSON structure documentation for the Regions Bank Account entity (FDX-compliant)",
  "fields": [
    { "name": "accountId", "type": "string", "required": true, "description": "Unique account identifier" },
    { "name": "accountType", "type": "string", "required": true, "description": "CHECKING, SAVINGS, CREDIT_CARD, LOAN, INVESTMENT, or MORTGAGE" },
    { "name": "accountNumber", "type": "string", "required": false, "description": "Masked account number (last 4 digits)" },
    { "name": "nickname", "type": "string", "required": false, "description": "Customer-assigned nickname" },
    { "name": "status", "type": "string", "required": true, "description": "OPEN or CLOSED" },
    { "name": "currency", "type": "string", "required": false, "description": "ISO 4217 currency code (default USD)" },
    { "name": "balance.available", "type": "number", "required": false, "description": "Available balance" },
    { "name": "balance.current", "type": "number", "required": false, "description": "Current ledger balance" },
    { "name": "balance.limit", "type": "number", "required": false, "description": "Credit limit (credit accounts)" },
    { "name": "balance.asOf", "type": "date-time", "required": false, "description": "Balance as-of timestamp" },
    { "name": "institution", "type": "string", "required": false, "description": "Institution name" }
  ]
}