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

{
  "markets": [
    {
      "ticker": "<string>",
      "title": "<string>",
      "contract_size": "<string>",
      "fractional_trading_enabled": true,
      "leverage_estimate": 123,
      "price": "0.5600",
      "volume": "10.00",
      "open_interest": "10.00",
      "volume_24h": "10.00",
      "bid": "0.5600",
      "ask": "0.5600"
    }
  ]
}