Coinbase price premium vs composite spot median (OKX + Kraken + Binance)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x36038e1d712c5e39f35952164ec58ec2b96caee7",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "20000",
    "maxTimeoutSeconds": 300
  }
]

{
  "bazaar": {
    "info": {
      "input": {
        "method": "GET",
        "pathParams": {},
        "queryParams": {},
        "type": "http"
      },
      "output": {
        "example": {
          "as_of": "2026-01-01T00:00:00.000Z",
          "asset": "BTC-USD",
          "available": true,
          "coinbase_price": 61320.5,
          "composite_median": 61198.3,
          "composite_source_count": 3,
          "disclaimer": "Cross-exchange premium is informational only. Spread may reflect latency, liquidity, or fees — not a pure demand signal. Not financial advice.",
          "historical_note": "Point-in-time only — no 24h percentile or 30d z-score (no historical baseline stored).",
          "interpretation": "Coinbase is trading at a +0.20% premium to global composite. Mild US/institutional demand bias.",
          "premium_pct": 0.2,
          "sources_used": [
            {
              "exchange": "coinbase",
              "price": 61320.5,
              "role": "reference"
            },
            {
              "exchange": "okx",
              "price": 61195.2,
              "role": "composite"
            },
            {
              "exchange": "kraken",
              "price": 61201.4,
              "role": "composite"
            },
            {
              "exchange": "binance",
              "price": 61198.3,
              "role": "composite"
            }
          ]
        },
        "example_kind": "illustrative_schema_only",
        "example_note": "Placeholder values and timestamps, not market data.",
        "type": "json"
      }
    },
    "routeTemplate": ":var1",
    "schema": {
      "$schema": "https://json-schema.org/draft/2020-12/schema",
      "properties": {
        "input": {
          "additionalProperties": false,
          "properties": {
            "method": {
              "enum": [
                "GET"
              ],
              "type": "string"
            },
            "pathParams": {
              "type": "object"
            },
            "queryParams": {
              "properties": {},
              "type": "object"
            },
            "type": {
              "const": "http",
              "type": "string"
            }
          },
          "required": [
            "type",
            "method"
          ],
          "type": "object"
        },
        "output": {
          "properties": {
            "example": {
              "type": "object"
            },
            "type": {
              "type": "string"
            }
          },
          "required": [
            "type"
          ],
          "type": "object"
        }
      },
      "required": [
        "input"
      ],
      "type": "object"
    }
  }
}

curl "https://kronossignals.com/api/v1/cex-premium/btc"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

const res = await fetch("https://kronossignals.com/api/v1/cex-premium/btc");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

import httpx
res = httpx.get("https://kronossignals.com/api/v1/cex-premium/btc")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header