# Polymarket API

> Polymarket returns prediction market odds, trading volumes, and chance history as a workflow and API.

Polymarket, also called Poly, Search markets finds topic-related markets ranked by total trading volume; enter a topic. List trending markets returns open markets ranked by 24-hour trading volume; optionally choose a category and result count. Get odds history shows an outcome’s chances over time; enter a market question or link, and optionally choose a period and outcome.

- Page: https://fous.com/workflows/polymarket
- Handle: `@polymarket`
- Category: [Finance](https://fous.com/workflows/category/finance)
- Source website: https://polymarket.com
- Last verified: Sep 29, 2026
- Fous is not affiliated with Polymarket.

## Methods

### Get odds history

Operation `get_odds_history`, version 1. 1 credit per call.

Show how a Polymarket outcome’s chance changed over time from a market question or link. Among matching markets, use the highest-volume match. Closed markets may have no points in recent periods.

**Input**

| Field | Type | Required | Example | Description |
|---|---|---|---|---|
| `market` | string | yes | `"https://polymarket.com/event/xi-jinping-out-before-2027"` | The market question or a Polymarket market link, for example "Xi Jinping out before 2027?". |
| `period` | string | no | `"last_month"` | How far back to show, for example "last_week". Defaults to last_month. |
| `outcome` | string | no | `"No"` | Outcome to track, for example "No". Defaults to the first outcome, usually Yes. |

**Input schema**

```json
{
  "type": "object",
  "required": [
    "market"
  ],
  "properties": {
    "market": {
      "type": "string",
      "description": "The market question or a Polymarket market link, for example \"Xi Jinping out before 2027?\".",
      "examples": [
        "https://polymarket.com/event/xi-jinping-out-before-2027",
        "Xi Jinping out before 2027?",
        "Fed rate cut by December 2025 meeting?"
      ]
    },
    "period": {
      "enum": [
        "last_day",
        "last_week",
        "last_month",
        "all_time"
      ],
      "type": "string",
      "default": "last_month",
      "description": "How far back to show, for example \"last_week\". Defaults to last_month.",
      "examples": [
        "last_month",
        "last_week",
        "all_time"
      ]
    },
    "outcome": {
      "type": "string",
      "default": "",
      "description": "Outcome to track, for example \"No\". Defaults to the first outcome, usually Yes.",
      "examples": [
        "No"
      ]
    }
  },
  "additionalProperties": false,
  "examples": [
    {
      "market": "https://polymarket.com/event/xi-jinping-out-before-2027",
      "period": "last_month",
      "outcome": "No"
    },
    {
      "market": "Xi Jinping out before 2027?",
      "period": "last_week"
    },
    {
      "market": "Fed rate cut by December 2025 meeting?",
      "period": "all_time"
    }
  ]
}
```

**Output**

| Field | Type | Example | Description |
|---|---|---|---|
| `points` | array |  | Historical chances in time order, at hourly or daily spacing depending on the period. |
| `points[].date_time` | string | `"2026-08-30T00:00:23Z"` | Sample time in ISO 8601 UTC. |
| `points[].chance_percent` | number | `95.55` | Chance at this time, as a percentage. |
| `outcome` | string | `"No"` | The tracked outcome. |
| `question` | string | `"Xi Jinping out before 2027?"` | The matched market question. |
| `market_url` | string | `"https://polymarket.com/event/xi-jinping-out-before-2027"` | Link to the Polymarket event containing this market. |
| `current_chance_percent` | number | `96.45` | Current chance, as a percentage from 0 to 100. |

**Example input**

```json
{
  "market": "https://polymarket.com/event/xi-jinping-out-before-2027",
  "period": "last_month",
  "outcome": "No"
}
```

**Example output**

```json
{
  "points": [
    {
      "date_time": "2026-08-30T00:00:23Z",
      "chance_percent": 95.55
    },
    {
      "date_time": "2026-08-31T00:00:22Z",
      "chance_percent": 95.55
    },
    {
      "date_time": "2026-09-01T00:00:34Z",
      "chance_percent": 95.65
    }
  ],
  "outcome": "No",
  "question": "Xi Jinping out before 2027?",
  "market_url": "https://polymarket.com/event/xi-jinping-out-before-2027",
  "current_chance_percent": 96.45
}
```

### List trending markets

Operation `list_trending_markets`, version 1. 1 credit per call.

List the most-traded open Polymarket markets, ranked by 24-hour trading volume. Select a category or see all markets; markets outside the named categories are labeled Other.

**Input**

| Field | Type | Required | Example | Description |
|---|---|---|---|---|
| `category` | string | no | `"crypto"` | Category to list, such as crypto; all includes every category. |
| `max_results` | integer | no | `5` | Maximum number of markets to return, such as 20 (up to 50). |

**Input schema**

```json
{
  "type": "object",
  "properties": {
    "category": {
      "enum": [
        "all",
        "politics",
        "crypto",
        "sports",
        "economy",
        "tech",
        "culture"
      ],
      "type": "string",
      "default": "all",
      "description": "Category to list, such as crypto; all includes every category.",
      "examples": [
        "crypto",
        "culture",
        "all"
      ]
    },
    "max_results": {
      "type": "integer",
      "default": 20,
      "maximum": 50,
      "minimum": 1,
      "description": "Maximum number of markets to return, such as 20 (up to 50).",
      "x-fous-developer": true,
      "examples": [
        5,
        3,
        50
      ]
    }
  },
  "additionalProperties": false,
  "examples": [
    {
      "category": "crypto",
      "max_results": 5
    },
    {},
    {
      "category": "culture",
      "max_results": 3
    }
  ]
}
```

**Output**

| Field | Type | Example | Description |
|---|---|---|---|
| `markets` | array |  | Open markets in descending order of 24-hour trading volume. |
| `markets[].link` | string | `"https://polymarket.com/event/what-price-will-bitcoin-hit-in-september-2026"` | Polymarket event page for this market. |
| `markets[].slug` | string | `"will-bitcoin-dip-to-82pt5k-in-september-2026"` | Polymarket market slug. |
| `markets[].category` | string | `"Crypto"` | Market category. |
| `markets[].end_date` | string or null | `"2026-10-01"` | Scheduled market end date (YYYY-MM-DD). |
| `markets[].question` | string | `"Will Bitcoin dip to $82,500 in September?"` | Market question. |
| `markets[].market_id` | string | `"4797724"` | Polymarket market ID. |
| `markets[].volume_24h_usd` | number | `208708.63` | Trading volume over the last 24 hours in USD. |
| `markets[].leading_outcome` | string or null | `"Yes"` | Outcome with the highest current chance. |
| `markets[].total_volume_usd` | number | `446588.04` | Total trading volume in USD. |
| `markets[].leading_chance_percent` | number or null | `76.5` | Current chance for the leading outcome, in percent. |

**Example input**

```json
{
  "category": "crypto",
  "max_results": 5
}
```

**Example output**

```json
{
  "markets": [
    {
      "link": "https://polymarket.com/event/what-price-will-bitcoin-hit-in-september-2026",
      "slug": "will-bitcoin-dip-to-82pt5k-in-september-2026",
      "category": "Crypto",
      "end_date": "2026-10-01",
      "question": "Will Bitcoin dip to $82,500 in September?",
      "market_id": "4797724",
      "volume_24h_usd": 208708.63,
      "leading_outcome": "Yes",
      "total_volume_usd": 446588.04,
      "leading_chance_percent": 76.5
    },
    {
      "link": "https://polymarket.com/event/what-price-will-bitcoin-hit-in-september-2026",
      "slug": "will-bitcoin-dip-to-80k-in-september-2026-from-september-18",
      "category": "Crypto",
      "end_date": "2026-10-01",
      "question": "Will Bitcoin dip to $80,000 in September?",
      "market_id": "4689727",
      "volume_24h_usd": 165597.52,
      "leading_outcome": "No",
      "total_volume_usd": 536372.93,
      "leading_chance_percent": 82.65
    },
    {
      "link": "https://polymarket.com/event/clarity-act-signed-into-law-in-2026",
      "slug": "clarity-act-signed-into-law-in-2026",
      "category": "Crypto",
      "end_date": "2027-01-01",
      "question": "Clarity Act (H.R.3633) signed into law in 2026?",
      "market_id": "1163699",
      "volume_24h_usd": 152583.58,
      "leading_outcome": "No",
      "total_volume_usd": 23228936.07,
      "leading_chance_percent": 94.75
    }
  ]
}
```

### Search markets

Operation `search_markets`, version 1. 1 credit per call.

Find Polymarket prediction markets about a topic, ranked by total trading volume, with outcome chances and market details. Odds are the quoted outcome prices at the time of the search; 24-hour volume may be unavailable for some markets.

**Input**

| Field | Type | Required | Example | Description |
|---|---|---|---|---|
| `topic` | string | yes | `"Fed rate cut"` | Words describing the event to find, for example Fed rate cut. |
| `max_results` | integer | no | `5` | Maximum markets to return, for example 10. |
| `include_closed` | boolean | no | `true` | Include closed markets too, for example false. |

**Input schema**

```json
{
  "type": "object",
  "required": [
    "topic"
  ],
  "properties": {
    "topic": {
      "type": "string",
      "minLength": 1,
      "description": "Words describing the event to find, for example Fed rate cut.",
      "examples": [
        "Fed rate cut",
        "US election",
        "zzzzzxxyy__nonexistent"
      ]
    },
    "max_results": {
      "type": "integer",
      "default": 10,
      "maximum": 50,
      "minimum": 1,
      "description": "Maximum markets to return, for example 10.",
      "x-fous-developer": true,
      "examples": [
        5,
        50
      ]
    },
    "include_closed": {
      "type": "boolean",
      "default": false,
      "description": "Include closed markets too, for example false.",
      "examples": [
        true,
        false
      ]
    }
  },
  "additionalProperties": false,
  "examples": [
    {
      "topic": "Fed rate cut"
    },
    {
      "topic": "US election",
      "max_results": 5,
      "include_closed": true
    },
    {
      "topic": "Fed rate cut",
      "max_results": 50,
      "include_closed": false
    }
  ]
}
```

**Output**

| Field | Type | Example | Description |
|---|---|---|---|
| `markets` | array |  | Matching markets, highest total trading volume first. |
| `markets[].link` | string | `"https://polymarket.com/event/how-many-fed-rate-cuts-in-2026/will-no-fed-rate-cuts-happen-in-2026"` | Polymarket market page. |
| `markets[].slug` | string | `"will-no-fed-rate-cuts-happen-in-2026"` | Polymarket market slug. |
| `markets[].status` | string | `"open"` | Market status. |
| `markets[].end_date` | string or null | `"2027-01-01"` | Market end date. |
| `markets[].outcomes` | array |  | Outcome names and current chances in percent. |
| `markets[].question` | string | `"Will no Fed rate cuts happen in 2026?"` | Market question. |
| `markets[].market_id` | string | `"616902"` | Polymarket market ID. |
| `markets[].event_title` | string | `"How many Fed rate cuts in 2026?"` | Title of the enclosing event. |
| `markets[].volume_24h_usd` | number or null | `36527.688199000004` | 24-hour trading volume in USD, if available. |
| `markets[].total_volume_usd` | number or null | `8646599.003723001` | Lifetime trading volume in USD. |

**Example input**

```json
{
  "topic": "Fed rate cut"
}
```

**Example output**

```json
{
  "markets": [
    {
      "link": "https://polymarket.com/event/how-many-fed-rate-cuts-in-2026/will-no-fed-rate-cuts-happen-in-2026",
      "slug": "will-no-fed-rate-cuts-happen-in-2026",
      "status": "open",
      "end_date": "2027-01-01",
      "outcomes": [
        {
          "name": "Yes",
          "chance_percent": 96.95
        },
        {
          "name": "No",
          "chance_percent": 3.05
        }
      ],
      "question": "Will no Fed rate cuts happen in 2026?",
      "market_id": "616902",
      "event_title": "How many Fed rate cuts in 2026?",
      "volume_24h_usd": 36527.688199000004,
      "total_volume_usd": 8646599.003723001
    },
    {
      "link": "https://polymarket.com/event/how-many-fed-rate-cuts-in-2026/will-11-fed-rate-cuts-happen-in-2026",
      "slug": "will-11-fed-rate-cuts-happen-in-2026",
      "status": "open",
      "end_date": "2027-01-01",
      "outcomes": [
        {
          "name": "Yes",
          "chance_percent": 0.05
        },
        {
          "name": "No",
          "chance_percent": 99.95
        }
      ],
      "question": "Will 11 Fed rate cuts happen in 2026?",
      "market_id": "616913",
      "event_title": "How many Fed rate cuts in 2026?",
      "volume_24h_usd": null,
      "total_volume_usd": 5272133.838100998
    },
    {
      "link": "https://polymarket.com/event/how-many-fed-rate-cuts-in-2026/will-10-fed-rate-cuts-happen-in-2026",
      "slug": "will-10-fed-rate-cuts-happen-in-2026",
      "status": "open",
      "end_date": "2027-01-01",
      "outcomes": [
        {
          "name": "Yes",
          "chance_percent": 0.05
        },
        {
          "name": "No",
          "chance_percent": 99.95
        }
      ],
      "question": "Will 10 Fed rate cuts happen in 2026?",
      "market_id": "616912",
      "event_title": "How many Fed rate cuts in 2026?",
      "volume_24h_usd": null,
      "total_volume_usd": 4954179.949515998
    }
  ]
}
```

## Quick start

Call the API with a Fous API key (`FOUS_API_KEY`). To create one, turn on Developer mode in Fous Studio, then open Keys & connections → API keys (https://app.fous.com/keys).

```bash
# First set your key: export FOUS_API_KEY='YOUR_FOUS_API_KEY'
: "${FOUS_API_KEY:?Set FOUS_API_KEY before running this example}"

curl 'https://api.fous.com/v1/query' \
  --fail-with-body --silent --show-error --max-time 120 \
  -H "Authorization: Bearer $FOUS_API_KEY" \
  -H 'Content-Type: application/json' \
  --data-raw '{
  "api": "@polymarket",
  "visibility": "public",
  "operation": "get_odds_history",
  "version": 1,
  "input": {
    "market": "https://polymarket.com/event/xi-jinping-out-before-2027",
    "period": "last_month",
    "outcome": "No"
  },
  "response": {
    "format": "json"
  }
}'
```

```python
# Save as fous.py and run with python3 fous.py. No packages needed.
# First set your key: export FOUS_API_KEY='YOUR_FOUS_API_KEY'
import json
import os
import urllib.error
import urllib.request

api_key = os.environ.get("FOUS_API_KEY")
if not api_key:
    raise RuntimeError("Set FOUS_API_KEY before running this example")

body = json.loads("{\n  \"api\": \"@polymarket\",\n  \"visibility\": \"public\",\n  \"operation\": \"get_odds_history\",\n  \"version\": 1,\n  \"input\": {\n    \"market\": \"https://polymarket.com/event/xi-jinping-out-before-2027\",\n    \"period\": \"last_month\",\n    \"outcome\": \"No\"\n  },\n  \"response\": {\n    \"format\": \"json\"\n  }\n}")
request = urllib.request.Request(
    "https://api.fous.com/v1/query",
    data=json.dumps(body).encode("utf-8"),
    headers={
        "Authorization": f"Bearer {api_key}",
        "Content-Type": "application/json",
    },
    method="POST",
)
try:
    with urllib.request.urlopen(request, timeout=120) as response:
        result = json.load(response)
except urllib.error.HTTPError as error:
    raise RuntimeError(f"HTTP {error.code}: {error.read().decode('utf-8', errors='replace')}") from error
if result.get("success") is False:
    raise RuntimeError(result.get("error", {}).get("message", "Request failed"))
print(json.dumps(result["data"]["output"], indent=2))
```

```typescript
// Save as fous.mts and run with npx tsx fous.mts.
// First set your key: export FOUS_API_KEY='YOUR_FOUS_API_KEY'
const apiKey = process.env.FOUS_API_KEY;
if (!apiKey) throw new Error("Set FOUS_API_KEY before running this example");

const response = await fetch("https://api.fous.com/v1/query", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${apiKey}`,
    "Content-Type": "application/json",
  },
  signal: AbortSignal.timeout(120_000),
  body: JSON.stringify({
  "api": "@polymarket",
  "visibility": "public",
  "operation": "get_odds_history",
  "version": 1,
  "input": {
    "market": "https://polymarket.com/event/xi-jinping-out-before-2027",
    "period": "last_month",
    "outcome": "No"
  },
  "response": {
    "format": "json"
  }
}),
});
type ApiResult = { success: boolean; data?: { output: unknown }; error?: { message: string } };
const result: ApiResult = await response.json();
if (!response.ok || result.success === false) {
  throw new Error(result.error?.message ?? `HTTP ${response.status}`);
}
if (!result.data) throw new Error("Missing API response data");
console.log(result.data.output);
```

Or describe the data in plain language: send `{"api":"@polymarket","prompt":"Describe the data you need, with every detail"}` to the same URL. Fous fills in the input, runs the method that fits and returns only the fields you asked for; `data.route.calls[].request` is the exact call it made. Routing is free; the run costs the same.

## Use cases

- Compare outcome chances across markets about a topic
- Track changes in an outcome’s chance over time
- Review open markets with the highest 24-hour trading volume
- Find markets by category and compare leading outcomes
- Identify markets with high lifetime trading volume

## FAQ

### Is Fous affiliated with Polymarket?

No. Fous is not affiliated with Polymarket. This workflow reads the public polymarket.com website and returns its data.

### How much does it cost?

Each run costs 1 credit. With pay-as-you-go, a credit costs 1¢; monthly plans cost less per credit.

### Do I need a Polymarket account?

No. You only need a Fous account.

### How current is the data?

Fous gets the data from polymarket.com when you run it; repeating the same request within a day may return the saved result. Fous checks this workflow automatically; it last passed a check on Sep 29, 2026.

### What are the current chances for markets about a topic?

Use Search markets with a topic to see outcome chances and market details, ranked by total trading volume.

### Which open markets have the highest 24-hour trading volume?

Use List trending markets to see open markets ranked by 24-hour trading volume, optionally filtered by category.

### How has an outcome’s chance changed over time?

Use Get odds history with a market question or link, and optionally specify a period and outcome.

## Related

- [CoinMarketCap API](https://fous.com/workflows/coinmarketcap.md): CoinMarketCap returns prices, rankings and current Fear and Greed readings; gainers and losers include up to 30 top-100 coins above $50,000 in 24-hour volume.
- [CoinGecko API](https://fous.com/workflows/coingecko.md): CoinGecko returns cryptocurrency prices and histories, sector rankings and details, and trending coins; non-USD historical values cover 365 days, histories 7–365 days, and today’s prices may change.
- [CompaniesMarketCap API](https://fous.com/workflows/companiesmarketcap.md): CompaniesMarketCap ranks public companies worldwide or by country and industry across size and financial measures, and provides company figures with market-cap history for completed years.
- [Yahoo Finance API](https://fous.com/workflows/yahoo-finance.md): Yahoo Finance provides quotes, movers, company financials, analyst ratings, earnings, news, and up to 5,000 price rows with adjusted returns; prices may be delayed.
- [MSN Money API](https://fous.com/workflows/msn-money.md): MSN Money provides stock quotes, key facts, financial news, and market data, including current market movers; quotes and prices may be delayed.
- [TradingView API](https://fous.com/workflows/tradingview.md): TradingView provides charts, markets, and technical analysis, with changing buy, sell, or neutral signals and stock screening; quotes may be delayed.
- [Macrotrends API](https://fous.com/workflows/macrotrends.md): Macrotrends provides long-term financial and economic charts, company metric histories, and yearly commodity and index prices; current-year prices may be incomplete.
- [Google Finance API](https://fous.com/workflows/google-finance.md): Google Finance returns possibly delayed prices and figures, indexes, up to four movers timed by oldest quote, currency conversions, and up to five financial periods.
- [All Finance workflows](https://fous.com/workflows/category/finance)