curl --request POST \
  --url https://api.grailpay.com/3p/api/v1/bank-account/{user_uuid} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "plaid": {
    "access_token": "access-token",
    "account_id": "account-id"
  },
  "custom": {
    "account_number": "12345678901234567",
    "routing_number": 123456789,
    "account_name": "John Doe",
    "account_type": "checking",
    "validate_account_routing": true
  },
  "billing_merchant_user_uuid": "a1b2c3d4-e5f6-g7h8-i9j0-k1l2m3n4o5p6",
  "billing_processor_mid": "1213121313"
}
'

{
  "status": true,
  "message": "Bank account has been added.",
  "data": {
    "uuid": "b1b9b3b0-0b3b-4b3b-8b3b-0b3b3b3b3b3b",
    "account_number": "1234567890",
    "routing_number": "123456789",
    "account_name": "John Doe",
    "account_type": "checking",
    "aggregator_type": "plaid",
    "created_at": "2021-10-01 00:00:00",
    "is_default": true
  },
  "errors": null,
  "error_code": null
}