Create outgoing invoice

Creates a new outgoing invoice or credit note with line items in a single transaction. The customer must exist. Invoice numbers are unique per customer.

POST /v1/outgoing-invoices

Authorization

Authorization string header required API key in the format ll_.... Pass as a Bearer token.

Request Body

customer_id uuid required Customer ID

document_id uuid optional Linked document (e.g. OCR scan)

invoice_number string required Invoice number (max 100)

invoice_date string required Invoice date (YYYY-MM-DD)

due_date string optional Due date (YYYY-MM-DD)

total_net number required Net amount

total_tax number required Tax amount

total_gross number required Gross amount

currency string optional Currency (3 characters, default: EUR)

type string required "invoice" or "credit_note"

intent_id uuid optional Linked journal intent (sets status to open)

notes string optional Free-text notes (max 2000)

lines array required Invoice line items (min. 1)

Invoice line item

position integer required Line number (starting at 1)

description string required Description (max 500)

quantity number required Quantity (positive)

unit_price number required Unit price

tax_rate number required Tax rate (0–1, e.g. 0.19)

tax_amount number required Tax amount of the line

line_total number required Gross amount of the line

account_number string optional Revenue account for this line

Responses

201

Success

400

INVALID_INPUT Required fields are missing or values do not match the expected format.

404

CUSTOMER_NOT_FOUND

409

DUPLICATE_INVOICE_NUMBER

POST /v1/outgoing-invoices

cURL

-cmd">curl --request -method">POST -punct">\
  --url 'https://api.ledgerlou.de/v1/outgoing-invoices' -punct">\
  --header 'Authorization: Bearer ll_your_key' -punct">\
  --header 'Content-Type: application/json' -punct">\
  --data '{
  "customer_id": "b2c3d4e5-...",
  "invoice_number": "AR-2024-001",
  "invoice_date": "2024-03-15",
  "due_date": "2024-04-15",
  "total_net": 1000,
  "total_tax": 190,
  "total_gross": 1190,
  "type": "invoice",
  "lines": [
    {
      "position": 1,
      "description": "Beratungsleistung",
      "quantity": 1,
      "unit_price": 1000,
      "tax_rate": 0.19,
      "tax_amount": 190,
      "line_total": 1190
    }
  ]
}'

201 Response

JSON

{
  "id": "<string>"
}