Monitoring · x402 · early usage

Cross-platform arbitrage detection between Polymarket and Kalshi: matched markets, pric…

Cross-platform arbitrage detection between Polymarket and Kalshi: matched markets, price spreads, fee-adjusted EV. Coverage: liquid Polymarket markets in politics/geopolitics/elections/tech/economy/finance; low-volume long-tail, sports, culture, and weather a…

by polynews.news · discovered, not yet claimed by its owner · updated 2026-10-08

30d calls2

30d payers2

MethodGET

Outputjson

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

Tags: bazaar

Call contract

Method: GET
Input: query parameters
Output: json
Last paid call: 2026-10-08

Input example from Bazaar metadata

{
  "category": "politics",
  "limit": "50"
}

Output example

{
  "data": {
    "computedAt": "2026-05-12T04:25:00.000Z",
    "kalshiDataAgeSec": 45,
    "matchedMarkets": 73,
    "opportunities": [
      {
        "arbitrage": {
          "confidence": "high",
          "feeEstimate": 0.038,
          "impliedProfit": 0.052,
          "spreadNet": 0.052,
          "spreadRaw": 0.09,
          "type": "BUY_YES_POLY_NO_KALSHI"
        },
        "categoryPoly": "finance",
        "id": "0xpoly__BTC200K-26DEC31",
        "kalshiTitle": "BTC at or above $200,000 by Dec 31, 2026",
        "kalshiYesAsk": 0.41,
        "kalshiYesBid": 0.39,
        "matchConfidence": 0.87,
        "polymarketNoPrice": 0.68,
        "polymarketQuestion": "Will Bitcoin reach $200K by Dec 31, 2026?",
        "polymarketYesPrice": 0.32
      }
    ],
    "polymarketDataAgeSec": 30,
    "totalKalshiMarkets": 13802,
    "totalPolymarkets": 1074
  },
  "meta": {
    "endpoint": "/api/v1/arbitrage",
    "latencyMs": 1240,
    "tier": "alpha",
    "timestamp": "2026-05-12T04:30:00.000Z",
    "version": "v1"
  }
}

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/31075.json for the price and payment options.
Pay. Call GET https://polynews.news/api/v1/arbitrage. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, Solana, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.01 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base, Solana
Demand: 2 calls · 2 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.01	0x6ee49a7872844397Fb52870Cc07b308fFADC9427	300s
exact	Solana solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp	USDC	$0.01	76xzzgua9K8985GqGMwB946zTFtHvjTd9MfGoTYfys3d	300s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x6ee49a7872844397Fb52870Cc07b308fFADC9427",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "payTo": "76xzzgua9K8985GqGMwB946zTFtHvjTd9MfGoTYfys3d",
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 300
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "properties": {
        "data": {
          "properties": {
            "matchedMarkets": {
              "type": "number"
            },
            "opportunities": {
              "items": {
                "properties": {
                  "arbitrage": {
                    "description": "Fee-adjusted arb calc",
                    "properties": {
                      "confidence": {
                        "description": "high | medium | low",
                        "type": "string"
                      },
                      "impliedProfit": {
                        "description": "Fee-adjusted EV",
                        "type": "number"
                      },
                      "spreadNet": {
                        "description": "After fees",
                        "type": "number"
                      },
                      "spreadRaw": {
                        "type": "number"
                      },
                      "type": {
                        "description": "e.g. BUY_YES_POLY_NO_KALSHI",
                        "type": "string"
                      }
                    },
                    "type": "object"
                  },
                  "kalshiTitle": {
                    "type": "string"
                  },
                  "kalshiYesAsk": {
                    "type": "number"
                  },
                  "matchConfidence": {
                    "type": "number"
                  },
                  "polymarketQuestion": {
                    "type": "string"
                  },
                  "polymarketYesPrice": {
                    "type": "number"
                  }
                },
                "type": "object"
              },
              "type": "array"
            }
          },
          "type": "object"
        }
      },
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

Example shape — generated from the schema, not a captured live response

{
  "example": {
    "data": {
      "matchedMarkets": 0,
      "opportunities": [
        {
          "arbitrage": {
            "confidence": "string",
            "impliedProfit": 0,
            "spreadNet": 0,
            "spreadRaw": 0,
            "type": "string"
          },
          "kalshiTitle": "string",
          "kalshiYesAsk": 0,
          "matchConfidence": 0,
          "polymarketQuestion": "string",
          "polymarketYesPrice": 0
        }
      ]
    }
  },
  "type": "string"
}

Examples

curl

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

JavaScript

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

Python

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

Details

Provider: polynews.news
Endpoint: https://polynews.news/api/v1/arbitrage
Machine-readable: /resources/31075.json