curl --request GET \
  --url https://external-api.kalshi.com/trade-api/v2/series

{
  "series": [
    {
      "ticker": "<string>",
      "frequency": "<string>",
      "title": "<string>",
      "category": "<string>",
      "tags": [
        "<string>"
      ],
      "settlement_sources": [
        {
          "name": "<string>",
          "url": "<string>"
        }
      ],
      "contract_url": "<string>",
      "contract_terms_url": "<string>",
      "fee_multiplier": 123,
      "additional_prohibitions": [
        "<string>"
      ],
      "product_metadata": {},
      "volume_fp": "10.00",
      "last_updated_ts": "2023-11-07T05:31:56Z"
    }
  ]
}