curl --request GET \
  --url https://api.enterprise.sandbox.uphold.com/core/assets/{asset}/rates \
  --header 'Authorization: Bearer <token>'

{
  "rates": {
    "ETH": {
      "ask": "22.910619213684715739",
      "bid": "22.85842248147463121064",
      "mid": "22.88452084757967347482"
    },
    "GBP": {
      "ask": "47027.64159916551332431855",
      "bid": "46908.53407930127413227339",
      "mid": "46968.08783923339372829597"
    },
    "USD": {
      "ask": "61023.8527432818",
      "bid": "60946.4628910217",
      "mid": "60985.15781715175"
    }
  }
}