curl --request GET \
  --url https://api.cryptorank.io/v3/global/altcoin-index/chart \
  --header 'X-Api-Key: <api-key>'

{
  "data": {
    "data": [
      {
        "time": 1748908800000,
        "value": 54,
        "altcoinsMarketCap": "812345678901",
        "classification": "Altcoin Season"
      }
    ]
  },
  "status": {
    "usedCredits": 1,
    "timestamp": 1780000000000
  }
}