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End-to-end: overdue to collection

The stored invoice status is useful for display. The customer balance endpoint is the canonical answer when your system decides whether to restrict a service.

1. Check the balance

Section titled “1. Check the balance”
Terminal window
curl https://api.rieckflow.com/v1/customers/467a0d8d-b9b2-4df3-bf7b-17d649442890/balance \
  -H "Authorization: Bearer $RIECK_API_KEY"
{
  "data": {
    "outstandingOere": 156250,
    "overdueOere": 156250,
    "overdueCount": 1,
    "oldestDueDate": "2026-07-15",
    "daysOverdue": 20,
    "collectionsOere": 0,
    "pastDue": true
  }
}

Use pastDue for the decision and the amounts for explanation. Subscribe to customer.past_due and customer.settled to avoid polling every customer.

2. Let reminders run

Section titled “2. Let reminders run”

The reminder engine applies your configured cadence while enforcing the statutory floor. Use GET /v1/invoices/{id}/reminders to show sent attempts and the next planned action. In test mode, advance the sandbox clock instead of waiting several weeks.

3. Hand the invoice to collection

Section titled “3. Hand the invoice to collection”
Terminal window
curl -X POST https://api.rieckflow.com/v1/invoices/9b2f1c1e-6b87-4d9b-91a0-47c8d72b8440/collect \
  -H "Authorization: Bearer $RIECK_API_KEY" \
  -H "Idempotency-Key: collect-order-2041"

Rieck rejects the request until the legal prerequisites are satisfied. A successful call returns the collection case and sets collectionsCaseId on the invoice. Continue with GET /v1/cases/{caseId} and case events; do not create a second case in your own system.