register-payment

# Register Payment Exactly 3 API calls. Find invoice directly (no customer lookup), get payment type, register payment. ## Call 1: Find Unpaid Invoice Search ALL invoices directly — `customerId` is NOT required. On a fresh sandbox there are very few invoices. ``` GET /invoice?invoiceDateFrom=2020-01-01&invoiceDateTo=2030-12-31&fields=id,invoiceNumber,amount,amountOutstanding&count=50 ``` Find the invoice where `amountOutstanding > 0`. On a fresh sandbox there is typically only one unpaid invoice. ## Call 2: Get Payment Types ``` GET /invoice/paymentType?fields=id,description&count=50 ``` Use "Betalt til bank" or "Kontant" payment type. ## Call 3: Register Payment ``` PUT /invoice/<invoice_id>/:payment?paymentDate=2026-03-20&paymentTypeId=<type_id>&paidAmount=<amount> ``` Use `amountOutstanding` from call 1 as `paidAmount`. All parameters are query parameters, not JSON body. **Total: 3 calls, 0 errors.** ## Gotchas - No customer lookup needed — search invoices directly - `GET /invoice` requires `invoiceDateFrom` and `invoiceDateTo` — use wide range - Payment endpoint uses PUT with query params, not POST with JSON body - Use today's date for `paymentDate` - `paidAmount` should match `amountOutstanding` from the invoice (includes VAT)