Events

Billey fires six webhook events. That is the complete list — there are deliberately no *.updated or *.deleted events, and a POS sale fires nothing.

The catalogue

Event	Fires when	`data` shape
`invoice.created`	An invoice is created	Invoice
`invoice.sent`	An invoice transitions to Sent	Invoice
`invoice.paid`	An invoice transitions to Paid	Invoice
`expense.created`	An expense is created	Expense
`expense.paid`	An expense transitions to Paid	Expense
`client.created`	A client is created	Client

In every case data is byte-identical to what the REST GET for that resource returns — parse it with the same code you already use for the endpoint.

Example payload

An invoice.paid delivery:

{
  "id": "9f1b7c2a-3d4e-4f5a-8b6c-1d2e3f4a5b6c",
  "type": "invoice.paid",
  "created_at": "2026-07-21T10:15:30Z",
  "data": {
    "id": 42,
    "invoice_number": "2026-0042",
    "status": "paid",
    "is_credit_note": false,
    "currency": "EUR",
    "total": "1250.15",
    "paid_at": "2026-07-21T10:15:30Z",
    "client": { "id": 7, "name": "Example Client B.V." },
    "line_items": [ /* … */ ]
  }
}

What does not fire an event

No *.updated and no *.deleted for any resource. To track edits or removals, poll the endpoint with updated_after and include_deleted (see Pagination).
POS sales emit no webhook at all — the point-of-sale area has no API or webhook surface in v1.

Read Verifying signatures before you act on any of these, and the Overview for delivery, retries, and headers.

Something inaccurate or missing? support@billey.nl