curl --request GET \
  --url https://api.corebill.io/v1/invoices/{id} \
  --header 'Authorization: Bearer <token>'

{
  "data": {
    "id": "inv_m3n4o5p6q7r8",
    "invoice_number": "INV-2025-000001",
    "customer_id": "cus_a1b2c3d4e5f6",
    "status": "sent",
    "issue_date": "2025-04-01",
    "due_date": "2025-05-01",
    "total": 5220,
    "amount_paid": 0,
    "amount_due": 5220,
    "currency": "USD",
    "created_at": "2025-04-01T10:00:00.000Z",
    "subtotal": 5000,
    "discount_type": "percentage",
    "discount_value": 10,
    "discount_amount": 500,
    "subtotal_after_discount": 4500,
    "tax_rate": 16,
    "tax_amount": 720,
    "notes": "Net 30 payment terms",
    "payment_terms": "Net 30",
    "updated_at": "2025-04-01T10:05:00.000Z",
    "customer": {
      "id": "cus_a1b2c3d4e5f6",
      "name": "John Doe",
      "contact_email": "[email protected]"
    },
    "public_token": "1713182400000-k8x2m9p4q7w1",
    "items": [
      {
        "id": "di_y5z6a7b8c9d0",
        "item_name": "Web Development",
        "quantity": 40,
        "unit_price": 150,
        "subtotal": 6000,
        "total": 6000,
        "sort_order": 0,
        "description": "Full-stack web application development",
        "unit": "hour"
      }
    ]
  }
}