curl --request GET \
  --url https://api.zivio.net/api/v3/sales_invoices/{id} \
  --header 'X-API-Key: <api-key>' \
  --header 'zivio-tenant-id: <api-key>'

{
  "id": "1",
  "status": "draft",
  "job_id": "23",
  "job_summary": "Some text about the project",
  "net_total": "16000.00",
  "tax_total": "2000.00",
  "total": "18000.00",
  "ccy": "GBP",
  "due_on": "2023-11-07T05:31:56Z",
  "dated_on": "2023-11-07T05:31:56Z",
  "milestone_id": "435",
  "line_item_sheet_id": "234",
  "credit_note_id": "124",
  "is_credit_note": "null",
  "credit_note_reason": "invoice paid in error",
  "invoice_items": [
    {
      "id": "1",
      "invoice_id": "123",
      "milestone_id": "3654",
      "line_item_sheet_id": "3645",
      "purchase_order_line_id": "284",
      "description": "Some text about the item",
      "quantity": "10.0",
      "unit_type": "milestone",
      "billing_start": "YYYY-MM-DD",
      "billing_end": "YYYY-MM-DD",
      "ccy": "GBP",
      "unit_cost": "30000.00",
      "cis_type": "materials",
      "net_total_price": "30000.00",
      "tax_rate": "20.0",
      "tax_total": "6000.00",
      "total_price": "36000.00",
      "tax_type": {
        "id": "123",
        "label": "UK VAT",
        "tax_reference": "sales",
        "key": "cis_registered_contractors_deduction",
        "rate": "20.0",
        "country_code": "GB",
        "created_at": "2023-11-07T05:31:56Z",
        "updated_at": "2023-11-07T05:31:56Z",
        "archived": "false",
        "custom_fields": {
          "key": "value"
        }
      }
    }
  ],
  "created_at": "2023-11-07T05:31:56Z",
  "updated_at": "2023-11-07T05:31:56Z",
  "approved_at": "2023-11-07T05:31:56Z",
  "approved_by": {
    "id": "7158",
    "first_name": "Jack",
    "last_name": "Jones",
    "email": "jack_jones@example.com",
    "org_name": "Organisation Ltd",
    "org_id": "567",
    "business_unit": "Public Private Partnerships",
    "division": "Infastructure",
    "department": "Bridges",
    "vetting_status": "PASSED",
    "created_at": "2023-11-07T05:31:56Z",
    "updated_at": "2023-11-07T05:31:56Z",
    "custom_fields": {
      "key": "value"
    },
    "has_oversight": "<string>"
  },
  "client": {
    "id": "7158",
    "first_name": "Jack",
    "last_name": "Jones",
    "email": "jack_jones@example.com",
    "org_name": "Organisation Ltd",
    "org_id": "567",
    "business_unit": "Public Private Partnerships",
    "division": "Infastructure",
    "department": "Bridge Building",
    "vetting_status": "PASSED",
    "created_at": "2023-11-07T05:31:56Z",
    "updated_at": "2023-11-07T05:31:56Z",
    "custom_fields": {
      "key": "value"
    },
    "has_oversight": "<string>"
  },
  "client_org": {
    "id": "7158",
    "name": "Company Ltd",
    "is_external_client": "<string>",
    "created_at": "2023-11-07T05:31:56Z",
    "updated_at": "2023-11-07T05:31:56Z"
  },
  "supplier": {
    "id": "77",
    "name": "Company Inc",
    "email": "jack_jones@companyinc.com",
    "vetting_status": "PASSED",
    "tax_number": "9876543234",
    "tax_registered": "true",
    "created_at": "2023-11-07T05:31:56Z",
    "updated_at": "2023-11-07T05:31:56Z"
  }
}