# Polymarket Midpoint Price

> Polymarket Midpoint Price is a paid API for AI agents from proxy.suverse.io, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).

Returns the midpoint price (implied probability 0–1) for a Polymarket outcome token from the live CLOB order book

## Facts

- Endpoint: POST https://proxy.suverse.io/v1/data/polymarket-midpoint-price
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/polymarket-midpoint-price-409b8e29
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_DGGM0QdeAczIEaEdfxZzs

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 polymarket-midpoint-price-409b8e29 -d '<json body>'
```

Example prompt: What's the current implied probability for Polymarket outcome token 71321057495192610898174985455085197958934673310580272847596498780490842282082? I need the midpoint price from the live order book.

## When to prefer this

Use this endpoint when you need a real-time, live order-book-derived probability for a specific Polymarket outcome token and already have the token_id (obtainable from polymarket-market-detail). Prefer this over scraping Polymarket's UI or using cached data sources when you need the freshest possible implied probability for trading, monitoring, or display purposes.

## Known failure modes

- Invalid or unknown token_id returns an error or empty result
- Stale or illiquid markets may have wide spreads making the midpoint less reliable
- Payment failure (x402) if USDC balance is insufficient
- Network or Polymarket API downtime causing fetch failure

## How this service works

Midpoint price (implied probability, 0-1) for a Polymarket outcome token from the live order book. Free Polymarket CLOB data. token_id from polymarket-market-detail.

## Output

A numeric midpoint price between 0 and 1 representing the implied probability of the outcome, derived from the live Polymarket CLOB order book (mid-point between best bid and best ask).

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "properties": {}
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "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/polymarket-midpoint-price-409b8e29/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from proxy.suverse.io](https://www.zero.xyz/host/proxy.suverse.io/llms.txt)