# x402-factory Venue Odds Comparison

> x402-factory Venue Odds Comparison is a paid API for AI agents from x402-factory.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Returns per-venue implied and vig-adjusted probabilities with order book depth for a prediction market, plus cross-venue spread and disagreement flag.

## Facts

- Endpoint: GET https://x402-factory.com/v1/odds/compare/:slug
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-factory-venue-odds-comparison-b82d2919
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6mO9MfcsX67rt4IKcGrf0

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability x402-factory-venue-odds-comparison-b82d2919
```

Example prompt: Compare Kalshi and Polymarket odds for the 'fed-rate-cut-2025' market — I want to see the vig-adjusted probabilities for each venue, the cross-venue spread, and whether they disagree by more than 5 points.

## When to prefer this

Use this endpoint when you need a fair-value (vig-removed) probability comparison across Kalshi and Polymarket for a specific market, or when you want to detect cross-venue mispricing or significant disagreement. Prefer this over a raw price feed when you need the overround stripped out and order book depth context in one call.

## Known failure modes

- Unknown slug returns 404 or empty data
- Market no longer active returns stale or missing depth
- Payment failure via x402 returns 402 Payment Required
- Slug format violation (must be lowercase kebab-case) returns 400 validation error
- One venue may be temporarily unavailable, returning partial per_venue data

## How this service works

Per-venue implied vs vig-adjusted odds with summarized depth for one market — Venue-by-venue comparison for a market: implied probability, vig-adjusted probability (overround removed via the quoted book), summarized depth near the touch, plus the cross-venue spread and a disagreement flag when it exceeds 5 points.

## Output

An array of per-venue records (Kalshi, Polymarket) each with implied probability, vig-adjusted probability, and order book depth within 1¢ and 5¢ of the touch; plus a single cross-venue spread number and a boolean disagreement_flag that fires when the spread exceeds 5 percentage points.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object",
     "required": [
      "slug"
     ],
     "properties": {
      "slug": {
       "type": "string",
       "pattern": "^[a-z0-9]+(?:-[a-z0-9]+)*$"
      }
     }
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "data",
      "meta"
     ],
     "properties": {
      "data": {
       "type": "object",
       "required": [
        "per_venue",
        "venue_spread",
        "disagreement_flag"
       ],
       "properties": {
        "per_venue": {
         "type": "array",
         "items": {
          "type": "object",
          "required": [
           "venue",
           "implied_p",
           "vig_adjusted_p",
           "depth_within_1c_usd",
           "depth_within_5c_usd"
          ],
          "properties": {
           "venue": {
            "enum": [
             "kalshi",
             "polymarket"
            ],
            "type": "string"
           },
           "implied_p": {
            "type": "number",
            "maximum": 1,
            "minimum": 0
           },
           "vig_adjusted_p": {
            "type": "number",
            "maximum": 1,
            "minimum": 0
           },
           "depth_within_1c_usd": {
            "type": "number"
           },
           "depth_within_5c_usd": {
            "type": "number"
           }
          },
          "additionalProperties": false
         }
        },
        "venue_spread": {
         "type": "number",
         "maximum": 1,
         "minimum": 0
        },
        "disagreement_flag": {
         "type": "boolean"
        }
       },
       "additionalProperties": false
      },
      "meta": {
       "type": "object"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-factory-venue-odds-comparison-b82d2919/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-factory.com](https://www.zero.xyz/host/x402-factory.com/llms.txt)