Create voucher
Book a voucher with rows of account, debit and credit in a voucher series.
MCP tool fortnox_write → create_voucher
write Confirm
Books one voucher with a transaction date, a description, a voucher series and rows. Each row has an account and either a debit or a credit amount; debits must equal credits. The date must fall inside an existing financial year and every account must exist and be active, or Fortnox rejects the voucher. Returns the series and voucher number. By default you confirm each call; you can switch that off for this tool.
Parameters
| Name | Type | Description |
|---|---|---|
| voucher_series string required | string | Voucher series code, e.g. A. |
| transaction_date date required | date | Booking date, inside an existing financial year. |
| description string required | string | Voucher description. |
| rows array required | array | Objects with account and either debit or credit. |
tools/call
{
"jsonrpc": "2.0",
"id": 1,
"method": "tools/call",
"params": {
"name": "fortnox_write",
"arguments": {
"operation": "create_voucher",
"arguments": {
"voucher_series": "A",
"transaction_date": "2026-10-31",
"description": "Accrued rent, October",
"rows": [
{
"account": "5010",
"debit": 8000
},
{
"account": "2990",
"credit": 8000
}
]
}
}
}
}Example response
{
"content": [
{
"type": "text",
"text": "{ ... same JSON as structuredContent ... }"
}
],
"structuredContent": {
"voucher_series": "A",
"voucher_number": 142,
"transaction_date": "2026-10-31",
"description": "Accrued rent, October",
"rows": [
{
"account": "5010",
"debit": 8000,
"credit": 0
},
{
"account": "2990",
"debit": 0,
"credit": 8000
}
]
},
"isError": false
}