GET /v1/probability/{slug}

$0.02realtimetier: datacache 5sEngine A — Probability API

Liquidity-weighted blend of venue implied probabilities for a canonical market slug, with per-venue detail, cross-venue divergence, and the last 1h move. Resolved markets return 410 RESOLVED with the outcome. Find slugs via /v1/probability/search.

Parameters

Example

curl "https://x402-factory.com/v1/probability/fed-rate-cut-2026-09"

Example response

{
  "data": {
    "slug": "fed-rate-cut-2026-09",
    "question": "Will the Fed cut rates at the September 2026 FOMC meeting?",
    "probability": 0.7301,
    "per_venue": [
      {
        "venue": "kalshi",
        "market_id": "KXFEDRATECUT2026",
        "implied_p": 0.7359,
        "volume_24h_usd": 204455.43,
        "liquidity_score": 0.947
      },
      {
        "venue": "polymarket",
        "market_id": "fed-rate-cut-2026-09",
        "implied_p": 0.7264,
        "volume_24h_usd": 249729.17,
        "liquidity_score": 0.98
      }
    ],
    "divergence": 0.0095,
    "category": "economics",
    "resolution_date": "2026-09-16",
    "resolution_criteria_summary": "Resolves YES if the target range upper bound is lowered at the Sep 15–16 meeting.",
    "last_move_1h": -0.001
  },
  "meta": {
    "endpoint": "/v1/probability/{slug}",
    "version": "1.0.0",
    "generated_at": "2026-08-18T22:54:16.781Z",
    "freshness": "realtime",
    "sources": [
      "kalshi",
      "polymarket"
    ],
    "request_id": "req_00000000",
    "docs": "https://x402-factory.com/docs/probability.get",
    "data_mode": "live"
  }
}

Response schema (data payload)

{
  "type": "object",
  "properties": {
    "slug": {
      "type": "string"
    },
    "question": {
      "type": "string"
    },
    "probability": {
      "type": "number",
      "minimum": 0,
      "maximum": 1
    },
    "per_venue": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "venue": {
            "type": "string",
            "enum": [
              "kalshi",
              "polymarket"
            ]
          },
          "market_id": {
            "type": "string"
          },
          "implied_p": {
            "type": "number",
            "minimum": 0,
            "maximum": 1
          },
          "volume_24h_usd": {
            "type": "number"
          },
          "liquidity_score": {
            "type": "number",
            "minimum": 0,
            "maximum": 1
          }
        },
        "required": [
          "venue",
          "market_id",
          "implied_p",
          "volume_24h_usd",
          "liquidity_score"
        ],
        "additionalProperties": false
      }
    },
    "divergence": {
      "type": "number",
      "minimum": 0,
      "maximum": 1
    },
    "category": {
      "type": "string"
    },
    "resolution_date": {
      "type": "string"
    },
    "resolution_criteria_summary": {
      "type": "string"
    },
    "last_move_1h": {
      "type": "number"
    }
  },
  "required": [
    "slug",
    "question",
    "probability",
    "per_venue",
    "divergence",
    "category",
    "resolution_date",
    "resolution_criteria_summary",
    "last_move_1h"
  ],
  "additionalProperties": false
}

The platform wraps every payload in an envelope: { "data": …, "meta": { endpoint, version, generated_at, freshness, sources, request_id, docs, data_mode } }.

Payment (x402)

Unpaid requests receive 402 with payment requirements (accepts). Pay $0.02 in USDC on Base per call via an X-PAYMENT header — see docs.x402.org. With PAYMENT_MODE=disabled (local dev) the endpoint is open.

Errors