Invoices API

Create, manage, and send invoices. Supports sales invoices, quotes, credit notes, and incoming invoices.

Invoice Types

Type	German	Description
rechnung	Ausgangsrechnung	Sales invoice
angebot	Angebot	Quote / proposal
gutschrift	Gutschrift	Credit note
eingangsrechnung	Eingangsrechnung	Purchase invoice

List Invoices

GET /api/invoices?type=rechnung&status=offen&page=1&limit=25

Param	Type	Description
type	string	Filter by invoice type
status	string	entwurf, offen, teilbezahlt, bezahlt, storniert
customerId	uuid	Filter by customer
from / to	date	Date range (ISO 8601)

Create Invoice

POST /api/invoices

{
  "type": "rechnung",
  "customerId": "customer-uuid",
  "items": [
    {
      "position": 1,
      "description": "Web Development - March 2026",
      "unit": "hours",
      "quantity": 40,
      "unitPrice": "95.00",
      "taxRate": "20.00"
    }
  ],
  "notes": "Payment within 14 days.",
  "paymentTermDays": 14
}

Send via Email

POST /api/invoices/:id/send

{
  "to": "[email protected]",
  "subject": "Invoice RG-2026-0042",
  "message": "Please find your invoice attached."
}

Download PDF

GET /api/invoices/:id/pdf

Record Payment

POST /api/invoices/:id/payments

{
  "amount": "1900.00",
  "date": "2026-03-22",
  "method": "bank_transfer"
}

E-Invoice Formats

GET /api/invoices/:id/ebinterface   # Austrian standard
GET /api/invoices/:id/zugferd       # EU standard

Statuses

Status	Description
entwurf	Draft
offen	Open — sent to customer
teilbezahlt	Partially paid
bezahlt	Fully paid
storniert	Cancelled