Utilities · x402 · early usage

Prediction market arbitrage API for Polymarket, Kalshi, and Gemini

Prediction market arbitrage API for Polymarket, Kalshi, and Gemini. Finds full-cover YES plus NO combinations with positive net edge.

by api.seerium.xyz · 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

Prediction market arbitrage API for Polymarket, Kalshi, and Gemini. Finds full-cover YES plus NO combinations with positive net edge.

Tags: bazaar

Call contract

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

Input example from Bazaar metadata

{
  "includeIndicative": true,
  "limit": 3,
  "minEdge": 0,
  "sources": "polymarket,kalshi,gemini"
}

Output example

{
  "data": {
    "criteria": {
      "includeIndicative": true,
      "limit": 20,
      "minEdge": null,
      "outcome": null,
      "sources": [],
      "strategy": "full_cover"
    },
    "markets": 1200,
    "returned": 1,
    "rows": [
      {
        "edge": 0.04,
        "feeBuffer": 0.002,
        "grossEdge": 0.042,
        "id": "arb_full_cover_example",
        "key": "question:will example event happen by friday:date:2026-03-30",
        "legs": [
          {
            "conditionId": "0xexample",
            "endDateIso": "2026-03-30T00:00:00.000Z",
            "eventTicker": null,
            "eventTitle": "Example Event",
            "indicative": true,
            "marketSlug": "example-market",
            "marketTicker": null,
            "marketUrl": "https://polymarket.com/market/example-market",
            "outcome": "yes",
            "price": 0.42,
            "priceType": "ask",
            "question": "Will example event happen by Friday?",
            "seriesTicker": null,
            "side": "BUY",
            "size": null,
            "source": "polymarket",
            "tokenId": "poly_yes_token",
            "totalDepth": null
          },
          {
            "conditionId": "KXEXAMPLE",
            "endDateIso": "2026-03-30T00:00:00.000Z",
            "eventTicker": null,
            "eventTitle": "Example Event",
            "indicative": true,
            "marketSlug": "KXEXAMPLE",
            "marketTicker": "KXEXAMPLE",
            "marketUrl": "https://kalshi.com/markets/kxexample",
            "outcome": "no",
            "price": 0.54,
            "priceType": "ask",
            "question": "Will example event happen by Friday?",
            "seriesTicker": null,
            "side": "BUY",
            "size": null,
            "source": "kalshi",
            "tokenId": "KXEXAMPLE:NO",
            "totalDepth": null
          }
        ],
        "matchedOn": {
          "dateKey": "2026-03-30",
          "directionKey": null,
          "eventKey": "example event",
          "numericKey": null,
          "subjectKey": "will example event happen by friday"
        },
        "no": {
          "conditionId": "KXEXAMPLE",
          "endDateIso": "2026-03-30T00:00:00.000Z",
          "eventTicker": null,
          "eventTitle": "Example Event",
          "indicative": true,
          "marketSlug": "KXEXAMPLE",
          "marketTicker": "KXEXAMPLE",
          "marketUrl": "https://kalshi.com/markets/kxexample",
          "outcome": "no",
          "price": 0.54,
          "priceType": "ask",
          "question": "Will example event happen by Friday?",
          "seriesTicker": null,
          "side": "BUY",
          "size": null,
          "source": "kalshi",
          "tokenId": "KXEXAMPLE:NO",
          "totalDepth": null
        },
        "outcome": null,
        "question": "Will example event happen by Friday?",
        "requiresShort": false,
        "sources": [
          "polymarket",
          "kalshi"
        ],
        "strategy": "full_cover",
        "totalCost": 0.96,
        "yes": {
          "conditionId": "0xexample",
          "endDateIso": "2026-03-30T00:00:00.000Z",
          "eventTicker": null,
          "eventTitle": "Example Event",
          "indicative": true,
          "marketSlug": "example-market",
          "marketTicker": null,
          "marketUrl": "https://polymarket.com/market/example-market",
          "outcome": "yes",
          "price": 0.42,
          "priceType": "ask",
          "question": "Will example event happen by Friday?",
          "seriesTicker": null,
          "side": "BUY",
          "size": null,
          "source": "polymarket",
          "tokenId": "poly_yes_token",
          "totalDepth": null
        }
      }
    ],
    "sourceTimestamps": {
      "gemini": 1760000000000,
      "kalshi": 1760000000000,
      "polymarket": 1760000000000
    },
    "totalCandidates": 1,
    "totals": {
      "fullCover": 1,
      "gemini": 250,
      "groups": 80,
      "kalshi": 450,
      "polymarket": 500,
      "sameOutcomeSpread": 0
    },
    "updatedAt": "2026-03-25T11:59:30.000Z",
    "warnings": []
  },
  "meta": {
    "freshnessMs": 30000,
    "generatedAt": "2026-03-25T12:00:00.000Z",
    "requestId": "req_example_123",
    "updatedAt": "2026-03-25T11:59:30.000Z"
  },
  "product": {
    "accepts": [
      {
        "network": "eip155:8453",
        "payTo": "0x81832eEDe3a4ad96CB3D7cA09977636D912fd3D5",
        "price": "$0.1000",
        "scheme": "exact"
      },
      {
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "payTo": "2h752kAbb9z1jpdSzqMEYg9JHv6TPJ6T2BfAJMyjLFtZ",
        "price": "$0.1000",
        "scheme": "exact"
      }
    ],
    "id": "prediction-arb-full-cover",
    "method": "GET",
    "name": "Prediction Market Arb Full Cover",
    "networks": [
      "eip155:8453",
      "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp"
    ],
    "path": "/v1/prediction/arb/full-cover",
    "price": "$0.1000"
  },
  "service": "seerium-x402-api"
}

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/40010.json for the price and payment options.
Pay. Call GET https://api.seerium.xyz/v1/prediction/arb/full-cover. 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: $0.1 / 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	$0.1	0x81832eEDe3a4ad96CB3D7cA09977636D912fd3D5	300s
exact	Solana solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp	USDC	$0.1	2h752kAbb9z1jpdSzqMEYg9JHv6TPJ6T2BfAJMyjLFtZ	300s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x81832eEDe3a4ad96CB3D7cA09977636D912fd3D5",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "100000",
    "amountUsd": 0.1,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "payTo": "2h752kAbb9z1jpdSzqMEYg9JHv6TPJ6T2BfAJMyjLFtZ",
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "amount": "100000",
    "amountUsd": 0.1,
    "maxTimeoutSeconds": 300
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

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

{
  "example": {},
  "type": "string"
}

Examples

curl

curl "https://api.seerium.xyz/v1/prediction/arb/full-cover"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://api.seerium.xyz/v1/prediction/arb/full-cover");
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://api.seerium.xyz/v1/prediction/arb/full-cover")
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: api.seerium.xyz
Endpoint: https://api.seerium.xyz/v1/prediction/arb/full-cover
Machine-readable: /resources/40010.json