# x402-factory Odds Compare

> x402-factory Odds Compare is a paid API for AI agents from x402-factory.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-12).

Compares implied and vig-adjusted probabilities for a prediction market event across multiple venues (Kalshi, Polymarket) with liquidity depth data.

## Facts

- Endpoint: GET https://x402-factory.com/v1/odds/compare/%7Bslug%7D
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-factory-odds-compare-c346bcc8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_M9XgqLaiQneHBFtCS6bCo

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-odds-compare-c346bcc8
```

Example prompt: Compare the current odds on Kalshi and Polymarket for the 2024 US presidential election market — I want to see the vig-adjusted probabilities and whether there's a significant spread between the two venues.

## When to prefer this

Choose this endpoint when you need real-time, cross-venue probability comparison with liquidity depth for a specific prediction market event. It is ideal for arbitrage detection, best-execution routing, and probability normalization workflows. Prefer it over single-venue APIs when venue disagreement or vig-adjusted accuracy matters.

## Known failure modes

- Unknown or invalid slug returns 404 or empty data
- Payment not included returns HTTP 402 with payment requirements in headers
- Stale or unavailable market data may return reduced venue coverage
- Rate limiting or USDC payment failure on Base network causes request rejection
- Market slug format mismatch causes parameter parsing errors

## How this service works

Paid data APIs for AI agents: prediction-market analytics, weather intelligence, weather×market edge signals, and SEC/gov data. Paid endpoints use the x402 protocol (HTTP 402 + USDC on Base): call without payment to receive requirements, retry with an X-PAYMENT header. Machine-readable catalog: /llms.txt. Per-endpoint docs: /docs/{id}.

## Output

Returns per-venue implied and vig-adjusted probabilities, order book liquidity depth within 1¢ and 5¢ in USD for each venue (Kalshi, Polymarket), the spread between venues, and a boolean disagreement flag. Also includes metadata with data freshness timestamp, sources, and request ID.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {
   "per_venue": [
    {
     "venue": "kalshi",
     "implied_p": 0.5965,
     "vig_adjusted_p": 0.5985,
     "depth_within_1c_usd": 23836.81,
     "depth_within_5c_usd": 80347.82
    },
    {
     "venue": "polymarket",
     "implied_p": 0.5702,
     "vig_adjusted_p": 0.5716,
     "depth_within_1c_usd": 30913.64,
     "depth_within_5c_usd": 123491.05
    }
   ],
   "venue_spread": 0.0263,
   "disagreement_flag": false
  },
  "meta": {
   "docs": "https://x402-factory.com/docs/probability.odds-compare",
   "sources": [
    "kalshi",
    "polymarket"
   ],
   "version": "1.0.0",
   "endpoint": "/v1/odds/compare/{slug}",
   "data_mode": "live",
   "freshness": "realtime",
   "request_id": "req_00000000",
   "generated_at": "2026-08-21T03:58:58.156Z"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-factory-odds-compare-c346bcc8/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)