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

# Approve Invoice

> Approve a draft invoice for payment

## Path Parameters

<ParamField path="id" type="string" required>The invoice ID</ParamField>

<Note>
  Only invoices with `draft` status can be approved. Approved invoices generate an official invoice number and cannot be edited — only voided via a credit note.
</Note>

<RequestExample>
  ```bash cURL theme={null}
  curl -X POST "https://api.nevatal.com/api/v1/billing/invoices/inv_002/approve" \
    -H "Authorization: Bearer nvtl_your_api_key"
  ```
</RequestExample>

<ResponseExample>
  ```json 200 theme={null}
  {
    "id": "inv_002",
    "invoiceNumber": "FV-2025-0043",
    "status": "approved",
    "approvedAt": "2025-03-16T10:00:00Z"
  }
  ```

  ```json 422 theme={null}
  {
    "statusCode": 422,
    "error": "Unprocessable Entity",
    "message": "Invoice is not in draft status"
  }
  ```
</ResponseExample>