# Romny Cross-Venue Odds — RH vs Polymarket Probability Spreads

> Romny Cross-Venue Odds — RH vs Polymarket Probability Spreads is a paid API for AI agents from api.romny.dpdns.org, paid per call via x402, $0.1/call, status unknown (last checked 2026-10-19).

Returns probability spread comparisons between Robinhood and Polymarket on matched prediction-market contracts, filterable by direction and minimum spread threshold.

## Facts

- Endpoint: GET https://api.romny.dpdns.org/v1/rh/spreads?utm_source=zero.xyz
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-19
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/romny-cross-venue-odds-rh-vs-polymarket-probability-spreads-268dfe13
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_vga910LCjN168nVaKAs4G

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 romny-cross-venue-odds-rh-vs-polymarket-probability-spreads-268dfe13
```

Example prompt: Pull the top 20 cross-venue spreads where Robinhood is richer than Polymarket, with a minimum absolute spread of 5 probability points and a match confidence of at least 0.75.

## When to prefer this

Choose this endpoint when you need real-time cross-venue probability spread data between Robinhood and Polymarket on matched contracts, especially for arbitrage screening, mispricing detection, or comparative odds analysis. Prefer this over raw Polymarket or RH catalog endpoints when you need the differential (spread) rather than absolute prices.

## Known failure modes

- No contracts meet the minimum spread or confidence thresholds — returns empty result set
- Invalid enum value for 'side' parameter — returns 400 validation error
- Limit out of range (below 1 or above 200) — returns 400 error
- Upstream Robinhood or Polymarket data unavailable — may return stale or partial results
- Payment not provided or rejected — returns 402 Payment Required

## How this service works

RH vs Polymarket probability spreads on matched contracts

## Output

A list of matched prediction-market contract pairs (up to 200 rows) showing the RH probability, Polymarket probability, absolute spread, and match confidence score for each pair. Results are filterable by which venue is pricing higher and by minimum spread or confidence thresholds.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "side": {
       "enum": [
        "any",
        "rh_rich",
        "pm_rich"
       ],
       "type": "string",
       "description": "any | rh_rich | pm_rich"
      },
      "limit": {
       "type": "string",
       "description": "Max rows (1-200, default 50)"
      },
      "min_abs_spread": {
       "type": "string",
       "description": "Min |RH-PM| in probability points (default 0.03)"
      },
      "min_confidence": {
       "type": "string",
       "description": "Minimum match confidence 0-1 (default 0.6)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/romny-cross-venue-odds-rh-vs-polymarket-probability-spreads-268dfe13/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.romny.dpdns.org](https://www.zero.xyz/host/api.romny.dpdns.org/llms.txt)