curl --request POST \
  --url https://api.altostrat.io/workspaces/{workspaceId}/billing-accounts/{billingAccountId}/invoices/preview \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "subscription_id": "sub_a1b2c3d4e5f6g7h8",
  "items": [
    {
      "product_type": "locations",
      "quantity": 15,
      "interval": "month"
    }
  ],
  "cancel_subscription": false
}'

{
  "id": "in_1Kb...",
  "customer_id": "cus_...",
  "status": "paid",
  "amount_due": 999,
  "amount_paid": 999,
  "currency": "usd",
  "created_at": "2025-10-29T00:40:06.000000Z",
  "subtotal": 1099,
  "total": 999,
  "tax": 0,
  "discount_amount": 100,
  "discount_names": [
    "10% Off Coupon"
  ],
  "lines": [
    {
      "id": "il_1Kb...",
      "description": "10 × Locations",
      "amount": 1000,
      "currency": "usd",
      "quantity": 10,
      "price_id": "price_...",
      "unit_amount": 100,
      "product_name": "Locations"
    }
  ],
  "due_date": null,
  "hosted_invoice_url": "https://invoice.stripe.com/...",
  "invoice_pdf": "https://pay.stripe.com/...",
  "number": "AB123-001"
}