curl --request GET \
  --url https://api.helicone.ai/v1/stripe/subscription/preview-invoice \
  --header 'Authorization: <api-key>'

{
  "evaluators_usage": [
    {
      "model": "<string>",
      "provider": "<string>",
      "prompt_tokens": 123,
      "completion_tokens": 123,
      "total_count": 123,
      "amount": 123,
      "description": "<string>",
      "totalCost": {
        "prompt_token": 123,
        "completion_token": 123
      }
    }
  ],
  "experiments_usage": [
    {
      "model": "<string>",
      "provider": "<string>",
      "prompt_tokens": 123,
      "completion_tokens": 123,
      "total_count": 123,
      "amount": 123,
      "description": "<string>",
      "totalCost": {
        "prompt_token": 123,
        "completion_token": 123
      }
    }
  ],
  "total": 123,
  "tax": 123,
  "subtotal": 123,
  "discount": {
    "coupon": {
      "amount_off": 123,
      "percent_off": 123,
      "name": "<string>"
    }
  },
  "lines": {
    "data": [
      {
        "description": "<string>",
        "amount": 123,
        "id": "<string>"
      }
    ]
  },
  "next_payment_attempt": 123,
  "currency": "<string>"
}