curl --request GET \
  --url https://api.kas.fyi/v1/rpc/getFeeEstimate \
  --header 'x-api-key: <api-key>'

{
  "estimate": {
    "priorityBucket": {
      "feerate": 1.5,
      "estimatedSeconds": 30
    },
    "normalBuckets": [
      {
        "feerate": 1.5,
        "estimatedSeconds": 30
      }
    ],
    "lowBuckets": [
      {
        "feerate": 1.5,
        "estimatedSeconds": 30
      }
    ]
  }
}