curl --request GET \
  --url https://nexus.gerowallet.io/api/btc/mempool \
  --header 'Authorization: Bearer <token>'

{
  "count": 123,
  "vsize": 123,
  "totalFee": 123,
  "feeHistogram": [
    {
      "feerate": 123,
      "vsize": 123
    }
  ]
}