# x402 Polymarket Markets

> x402 Polymarket Markets is a paid API for AI agents from x402tap.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-12).

Search or list active Polymarket prediction markets, ranked by 24-hour trading volume

## Facts

- Endpoint: GET https://x402tap.com/api/polymarket-markets?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-polymarket-markets-159edd9c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XtI72r0URFHph5r_1ZuD0

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-polymarket-markets-159edd9c
```

Example prompt: Show me the top Polymarket prediction markets related to elections right now — return up to 20 results ranked by 24-hour volume.

## When to prefer this

Use this endpoint when you need to discover or search across active Polymarket prediction markets by topic, ranked by recent trading activity. It is best when you want a broad overview or filtered list rather than deep detail on a single market. Prefer this over exchange APIs or news sources when you want quantified crowd-probability estimates on future events. It complements Kalshi endpoints when you want Polymarket-specific liquidity and pricing data.

## Known failure modes

- No markets match the keyword query — returns empty markets array
- limit parameter out of range (must be 1-50) — may return error or default
- Payment not included or insufficient — 402 Payment Required response
- Polymarket data source temporarily unavailable — upstream error
- Invalid query parameter type — schema validation error

## How this service works

Search or list active Polymarket prediction markets, ranked by 24h volume

## Output

Returns a JSON object with a count of matched markets and an array of market objects, each including the market question, slug, active status, end date, possible outcomes, current outcome prices (probabilities), 24-hour volume, total volume, and liquidity.

## 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"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "q": {
       "type": "string",
       "description": "Optional keyword filter on the market question"
      },
      "limit": {
       "type": "string",
       "description": "Max markets to return, 1-50 (default 10)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "count": 1,
  "query": "election",
  "markets": [
   {
    "slug": "example-market",
    "active": true,
    "endDate": "2026-12-31T00:00:00Z",
    "outcomes": [
     "Yes",
     "No"
    ],
    "question": "Example prediction market?",
    "liquidity": 45678.9,
    "volume24hr": 12345.67,
    "volumeTotal": 987654.32,
    "outcomePrices": [
     0.62,
     0.38
    ]
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-polymarket-markets-159edd9c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402tap.com](https://www.zero.xyz/host/x402tap.com/llms.txt)