Utilities · x402 · early usage

Detect basket arbitrage in a Polymarket neg-risk (mutually-exclusive, multi-outcome) ev…

by alphapipeline-eu.onrender.com · discovered, not yet claimed by its owner · updated 2026-10-01

30d calls1

30d payers1

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

Detect basket arbitrage in a Polymarket neg-risk (mutually-exclusive, multi-outcome) event - since a full YES basket across all outcomes always settles to exactly $1, a basket price away from $1 is a near risk-free edge. Also computes buy/sell_basket_capacity_shares, the actual liquidity-bottleneck size executable right now, so this is not just a top-of-book mirage. Polymarket only (Kalshi's Data ToS forbids this use of their data). Paid in USDC on Base.

Tags: prediction-market · polymarket · arbitrage · bazaar

Call contract

Method: GET
Input: query parameters
Output: json
Last paid call: 2026-10-01

Input example from Bazaar metadata

{
  "event_slug": "presidential-election-winner-2028"
}

Output example

{
  "arbitrage_viable": true,
  "assumed_round_trip_cost_pct": 1.5,
  "basket_ask_sum": 0.94,
  "basket_bid_sum": 0.88,
  "buy_basket_capacity_notional_usd": 39.48,
  "buy_basket_capacity_shares": 42,
  "buy_basket_capacity_vwap_notional_usd": 39.71,
  "buy_basket_gross_edge_usd": 0.06,
  "buy_basket_net_edge_usd": 0.045,
  "data_source": "polymarket-gamma+clob",
  "event_slug": "presidential-election-winner-2028",
  "generated_at": {
    "kst": "2026-09-08 21:00:00 KST",
    "utc": "2026-09-08T12:00:00Z"
  },
  "notice": "*_capacity_shares is how many full baskets (1 share of every outcome) you could execute right now within max_slippage_pct of each leg's best price - arbitrage_viable=false with a positive edge usually means the edge is real but too thin to size meaningfully. *_capacity_notional_usd prices that capacity at each leg's top-of-book price, which is optimistic for any size beyond the first price level - *_capacity_vwap_notional_usd instead prices it by walking the same depth used to compute capacity_shares, so it reflects the actual average cost of filling that size (null if depth data was insufficient). oldest_book_snapshot_time is the staleness bottleneck across all legs. Cross-check the specific leg you intend to trade with prediction.exit_capacity_audit before sizing a real position.",
  "num_outcomes": 5,
  "oldest_book_snapshot_time": {
    "kst": "2026-09-08 20:59:58 KST",
    "utc": "2026-09-08T11:59:58Z"
  },
  "opportunity": "buy_basket",
  "sell_basket_capacity_notional_usd": 0,
  "sell_basket_capacity_shares": 0,
  "sell_basket_capacity_vwap_notional_usd": null,
  "sell_basket_gross_edge_usd": -0.12,
  "sell_basket_net_edge_usd": -0.135
}

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/30149.json for the price and payment options.
Pay. Call GET https://alphapipeline-eu.onrender.com/v1/prediction/neg-risk-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, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.03 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base
Demand: 1 calls · 1 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.03	0x2bcfA4F7E1fA5E96934846A7dEa623398Ed7f752	300s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x2bcfA4F7E1fA5E96934846A7dEa623398Ed7f752",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "30000",
    "amountUsd": 0.03,
    "maxTimeoutSeconds": 300
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "properties": {
        "arbitrage_viable": {
          "title": "Arbitrage Viable",
          "type": "boolean"
        },
        "assumed_round_trip_cost_pct": {
          "title": "Assumed Round Trip Cost Pct",
          "type": "number"
        },
        "basket_ask_sum": {
          "anyOf": [
            {
              "type": "number"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Basket Ask Sum"
        },
        "basket_bid_sum": {
          "anyOf": [
            {
              "type": "number"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Basket Bid Sum"
        },
        "buy_basket_capacity_notional_usd": {
          "anyOf": [
            {
              "type": "number"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Buy Basket Capacity Notional Usd"
        },
        "buy_basket_capacity_shares": {
          "title": "Buy Basket Capacity Shares",
          "type": "number"
        },
        "buy_basket_capacity_vwap_notional_usd": {
          "anyOf": [
            {
              "type": "number"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "description": "Same capacity as buy_basket_capacity_shares, but priced by walking the actual order-book depth (volume-weighted) instead of using each leg's top-of-book price - a more realistic fill cost than buy_basket_capacity_notional_usd. Null if depth data was insufficient.",
          "title": "Buy Basket Capacity Vwap Notional Usd"
        },
        "buy_basket_gross_edge_usd": {
          "anyOf": [
            {
              "type": "number"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Buy Basket Gross Edge Usd"
        },
        "buy_basket_net_edge_usd": {
          "anyOf": [
            {
              "type": "number"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Buy Basket Net Edge Usd"
        },
        "data_source": {
          "title": "Data Source",
          "type": "string"
        },
        "event_slug": {
          "title": "Event Slug",
          "type": "string"
        },
        "generated_at": {
          "properties": {
            "kst": {
              "title": "Kst",
              "type": "string"
            },
            "utc": {
              "title": "Utc",
              "type": "string"
            }
          },
          "required": [
            "utc",
            "kst"
          ],
          "title": "TimestampPair",
          "type": "object"
        },
        "notice": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Notice"
        },
        "num_outcomes": {
          "title": "Num Outcomes",
          "type": "integer"
        },
        "oldest_book_snapshot_time": {
          "anyOf": [
            {
              "properties": {
                "kst": {
                  "title": "Kst",
                  "type": "string"
                },
                "utc": {
                  "title": "Utc",
                  "type": "string"
                }
              },
              "required": [
                "utc",
                "kst"
              ],
              "title": "TimestampPair",
              "type": "object"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "description": "The oldest of each leg's own order-book snapshot timestamp - the staleness bottleneck across all legs, since the whole basket calculation is only as fresh as its stalest leg. Null if no leg reported a timestamp."
        },
        "opportunity": {
          "title": "Opportunity",
          "type": "string"
        },
        "sell_basket_capacity_notional_usd": {
          "anyOf": [
            {
              "type": "number"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Sell Basket Capacity Notional Usd"
        },
        "sell_basket_capacity_shares": {
          "title": "Sell Basket Capacity Shares",
          "type": "number"
        },
        "sell_basket_capacity_vwap_notional_usd": {
          "anyOf": [
            {
              "type": "number"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "description": "VWAP-priced equivalent of sell_basket_capacity_notional_usd - see buy_basket_capacity_vwap_notional_usd.",
          "title": "Sell Basket Capacity Vwap Notional Usd"
        },
        "sell_basket_gross_edge_usd": {
          "anyOf": [
            {
              "type": "number"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Sell Basket Gross Edge Usd"
        },
        "sell_basket_net_edge_usd": {
          "anyOf": [
            {
              "type": "number"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Sell Basket Net Edge Usd"
        }
      },
      "required": [
        "generated_at",
        "event_slug",
        "num_outcomes",
        "assumed_round_trip_cost_pct",
        "buy_basket_capacity_shares",
        "sell_basket_capacity_shares",
        "opportunity",
        "arbitrage_viable",
        "data_source"
      ],
      "title": "PredictionNegRiskArbitrageResponse",
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

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

{
  "example": {
    "arbitrage_viable": true,
    "assumed_round_trip_cost_pct": 0,
    "basket_ask_sum": null,
    "basket_bid_sum": null,
    "buy_basket_capacity_notional_usd": null,
    "buy_basket_capacity_shares": 0,
    "buy_basket_capacity_vwap_notional_usd": null,
    "buy_basket_gross_edge_usd": null,
    "buy_basket_net_edge_usd": null,
    "data_source": "string",
    "event_slug": "string",
    "generated_at": {
      "kst": "string",
      "utc": "string"
    },
    "notice": null,
    "num_outcomes": 0,
    "oldest_book_snapshot_time": null,
    "opportunity": "string",
    "sell_basket_capacity_notional_usd": null,
    "sell_basket_capacity_shares": 0,
    "sell_basket_capacity_vwap_notional_usd": null,
    "sell_basket_gross_edge_usd": null,
    "sell_basket_net_edge_usd": null
  },
  "type": "string"
}

Examples

curl

curl -X GET 'https://alphapipeline-eu.onrender.com/v1/prediction/neg-risk-arbitrage'
# -> 402 Payment Required; read PAYMENT-REQUIRED
# retry the identical request with PAYMENT-SIGNATURE

JavaScript

const res = await fetch("https://alphapipeline-eu.onrender.com/v1/prediction/neg-risk-arbitrage", {
  "method": "GET"
});
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.request("GET", "https://alphapipeline-eu.onrender.com/v1/prediction/neg-risk-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: alphapipeline-eu.onrender.com
Endpoint: https://alphapipeline-eu.onrender.com/v1/prediction/neg-risk-arbitrage
Machine-readable: /resources/30149.json