> ## Documentation Index
> Fetch the complete documentation index at: https://docs.helloproper.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Create one-time bill item

### Request

<ParamField body="leaseId" type="string" required>
  The lease for which one-time bill items will be created
</ParamField>

<ParamField body="oneTimeBillItem" type="object" required>
  <Expandable>
    <ParamField body="productKey" type="string" required>
      The key or identifier for the product or service billed (e.g., "key:rent")
    </ParamField>

    <ParamField body="description" type="string">
      The content of the description that is going to be put on the bill
    </ParamField>

    <ParamField body="amount" type="object" required>
      The amount charged for the one-time bill item

      <Expandable>
        <ParamField body="currency" type="string" required>
          The currency code for the one-time bill item amount (e.g., "DKK")
        </ParamField>

        <ParamField body="amount" type="number" required>
          The amount of the one-time bill item amount (e.g., 100.00)
        </ParamField>
      </Expandable>
    </ParamField>

    <ParamField body="quantity" type="Number">
      The quantity of items that is going to be put on the bill
    </ParamField>

    <ParamField body="dueDate" type="date" required>
      The date in ISO 8601 format that one-time bill item is due
    </ParamField>

    <ParamField body="accountingPeriod" type="string" required>
      The accounting period for the one-time bill item, in the format "YYYY-MM-DD/YYYY-MM-DD"
    </ParamField>

    <ParamField body="vat" type="object" required>
      The VAT details for the one-time bill item

      <Expandable>
        <ParamField body="taxMode" type="string" required>
          The tax mode for the VAT (e.g., "Exempt", "Exclusive")
        </ParamField>

        <ParamField body="taxRate" type="number">
          The tax rate for the VAT (e.g., 0.25)
        </ParamField>
      </Expandable>
    </ParamField>
  </Expandable>
</ParamField>

### Response

<ResponseField name="oneTimeBillItemId" type="string">
  The unique identifier for the created one-time bill item
</ResponseField>

<ResponseField name="dueDate" type="date">
  The due date in ISO 8601 format of the one-time bill item
</ResponseField>