Create invoice
Save a customer invoice with dates and rows. It is saved, not booked and not sent.
POST https://cotlet.dev/api/v1/fortnox/customers/{customer_number}/invoices
write Confirm
Creates a customer invoice for an existing customer from the rows you give and returns its number and totals. The invoice is saved, so it can still be changed in Fortnox; it is not booked and not sent until bookkeep_invoice and send_invoice run. Each row needs a description or an article_number, a quantity and a unit price. Invoice and due date default to the customer terms in Fortnox. By default you confirm each call; you can switch that off for this tool.
Parameters
| Name | Type | Description |
|---|---|---|
| customer_number string required | string | Customer number from list_customers. |
| invoice_date date | date | Invoice date. Default: today. |
| due_date date | date | Due date. Default: from the customer payment terms. |
| rows array required | array | Objects with article_number or description, quantity, unit_price and optional discount_percent. |
| comments string | string | Text shown on the invoice. |
Request
curl -X POST https://cotlet.dev/api/v1/fortnox/customers/1042/invoices \
-H "Authorization: Bearer $COTLET_API_KEY" \
-H "Content-Type: application/json" \
-d '{"invoice_date":"2026-10-14","due_date":"2026-11-13","rows":[{"description":"Consulting, October","quantity":10,"unit_price":1200}]}'result = client.call("fortnox", "create_invoice", {"customer_number":"1042","invoice_date":"2026-10-14","due_date":"2026-11-13","rows":[{"description":"Consulting, October","quantity":10,"unit_price":1200}]})const result = await cotlet.call('fortnox', 'create_invoice', {"customer_number":"1042","invoice_date":"2026-10-14","due_date":"2026-11-13","rows":[{"description":"Consulting, October","quantity":10,"unit_price":1200}]});cotlet call fortnox create_invoice --data '{"customer_number":"1042","invoice_date":"2026-10-14","due_date":"2026-11-13","rows":[{"description":"Consulting, October","quantity":10,"unit_price":1200}]}'Example response
{
"invoice_number": "2381",
"customer_number": "1042",
"customer": "Nordlys Design AB",
"state": "saved",
"sent": false,
"invoice_date": "2026-10-14",
"due_date": "2026-11-13",
"net": 12000,
"vat": 3000,
"total": 15000,
"currency": "SEK"
}