# polymarket.markets

**stable** **Advanced**

Top active prediction markets by 24h volume (Gamma).

`GET /v1/polymarket/markets`

## What you get

A list of Polymarket results in Onekey's unified shape, in `data` (an array). An empty array is a normal, successful answer and is charged like any other; a source that reports "nothing found" as an error returns a free `404 not_found` instead.

## What it costs

- **Advanced · 5 credits** for a fresh fetch, charged only when it succeeds.
- **Free when served from cache (0.2 credit for a cached response over 100 KB).**
- **Free** if the request is invalid (never charged) or the source fails or reports not found (refunded).

## Parameters

| Name | Type | Required | Default | What it is | Constraints |
| --- | --- | --- | --- | --- | --- |
| `limit` | string | no | `20` | Rows (1-100) | max 3 chars; must match `[1-9]\d?\|100`; trimmed |

## Request

```bash
curl "https://api.onekey.dev/v1/polymarket/markets?limit=5" \
  -H "x-api-key: YOUR_API_KEY"
```

```python
import requests

res = requests.get(
    "https://api.onekey.dev/v1/polymarket/markets",
    params={"limit": "5"},
    headers={"x-api-key": "YOUR_API_KEY"},
)
body = res.json()

if body["success"]:
    print(body["data"])
else:
    print(body["error"]["code"], body["error"]["message"])
```

```javascript
const params = new URLSearchParams({ limit: "5" });
const res = await fetch(`https://api.onekey.dev/v1/polymarket/markets?${params}`, {
  headers: { "x-api-key": "YOUR_API_KEY" },
});
const body = await res.json();

if (body.success) console.log(body.data);
else console.error(body.error.code, body.error.message);
```

## Recorded response

A real Polymarket response, recorded and returned in Onekey's shape. Fields the platform does not provide are `null`.

```json
{
  "success": true,
  "data": [
    {
      "entity": {
        "id": "4581768",
        "name": "Will France win on 2026-09-28?",
        "slug": "unl-bel-fra-2026-09-28-fra",
        "description": "In the upcoming game, scheduled for September 28, 2026\nIf France wins, this market will resolve to \"Yes\".\nOtherwise, this market will resolve to \"No\".\nIf the game is postponed, this market will remain open until the game has been completed.\nIf the game is canceled entirely, with no make-up game, this market will resolve \"No\".\nThis market refers only to the outcome within the first 90 minutes of re",
        "date": "2026-09-28T18:45:00Z"
      },
      "media": {
        "thumbnailUrl": "https://polymarket-upload.s3.us-east-2.amazonaws.com/soccer-leagues/unl.png"
      },
      "market": {
        "volume": 3781854.5237449966,
        "liquidity": 85157.6582,
        "volume24h": 3582687.5046109967,
        "price": 0.45,
        "bid": 0.45,
        "ask": 0.48,
        "change24h": -0.05
      },
      "ext": {
        "outcomes": "[\"Yes\", \"No\"]",
        "outcomePrices": "[\"0.465\", \"0.535\"]",
        "tokenIds": "[\"110842582318648062017260301759054663836028300201858808991939499354773358824458\", \"6570736768586531778305906800330243503420851954788128056678194310642051325190\"]",
        "conditionId": "0xe40546397445aa9bfcc7017184a52197e74af1539e71a1afa2b443e21dd2db64",
        "active": true,
        "closed": false
      }
    },
    {
      "entity": {
        "id": "4581765",
        "name": "Will Belgium win on 2026-09-28?",
        "slug": "unl-bel-fra-2026-09-28-bel",
        "description": "In the upcoming game, scheduled for September 28, 2026\nIf Belgium wins, this market will resolve to \"Yes\".\nOtherwise, this market will resolve to \"No\".\nIf the game is postponed, this market will remain open until the game has been completed.\nIf the game is canceled entirely, with no make-up game, this market will resolve \"No\".\nThis market refers only to the outcome within the first 90 minutes of r",
        "date": "2026-09-28T18:45:00Z"
      },
      "media": {
        "thumbnailUrl": "https://polymarket-upload.s3.us-east-2.amazonaws.com/soccer-leagues/unl.png"
      },
      "market": {
        "volume": 1397412.7940300002,
        "liquidity": 56687.7329,
        "volume24h": 1371144.8430900003,
        "price": 0.2,
        "bid": 0.17,
        "ask": 0.19,
        "change24h": -0.075
      },
      "ext": {
        "outcomes": "[\"Yes\", \"No\"]",
        "outcomePrices": "[\"0.18\", \"0.82\"]",
        "tokenIds": "[\"67144485481037824353658978599351365276404964132594238946384478254500444104495\", \"25618814946951455596920857136845723066153921784361858128141971994013676014089\"]",
        "conditionId": "0x3d0e110a6fb9ae0caebe8808b40b7e27de398af0d373e69ea6abb9bdbae61b3e",
        "active": true,
        "closed": false
      }
    }
  ],
  "metadata": {
    "platform": "polymarket",
    "endpoint": "markets",
    "cached": false,
    "stale": false,
    "age_s": 0,
    "fetched_at": "2026-01-01T12:00:00+00:00",
    "credits_charged": 5,
    "request_id": "7f3a9c2e5b1d4c8fa2e6d0b9c4f18e37"
  },
  "error": null
}
```

## Field mapping

How this endpoint's source fields become Onekey's [unified schema](https://onekey.dev/docs/schema.md). Fields the source lacks come back as `null`.

| Source path | Onekey field | Transform |
| --- | --- | --- |
| `id` | `entity.id` | `toString` |
| `question` | `entity.name` | - |
| `slug` | `entity.slug` | - |
| `description` | `entity.description` | - |
| `image` | `media.thumbnailUrl` | `safeUrl` |
| `endDate` | `entity.date` | `toIsoDate` |
| `volume` | `market.volume` | `toNumber` |
| `liquidity` | `market.liquidity` | `toNumber` |
| `volume24hr` | `market.volume24h` | `toNumber` |
| `lastTradePrice` | `market.price` | `toNumber` |
| `bestBid` | `market.bid` | `toNumber` |
| `bestAsk` | `market.ask` | `toNumber` |
| `oneDayPriceChange` | `market.change24h` | `toNumber` |
| `outcomes` | `ext.outcomes` | - |
| `outcomePrices` | `ext.outcomePrices` | - |
| `clobTokenIds` | `ext.tokenIds` | - |
| `conditionId` | `ext.conditionId` | - |
| `active` | `ext.active` | `toBoolean` |
| `closed` | `ext.closed` | `toBoolean` |

## Caching and freshness

- Fresh for about 2 minutes. Repeat calls in that window are served from cache and are free.
- Between 2 minutes and 15 minutes the cached copy is still served instantly and marked `stale: true` while Onekey refreshes it in the background.
- If the source is down when a refresh is needed, the last copy can be served for up to 1 hour more (marked stale).
- A "not found" is remembered for 1 minute and is free.
- The cache is shared across all customers, which is what keeps repeat calls cheap.

## What can go wrong

| Status | Code | What to do |
| --- | --- | --- |
| 401 | `unauthorized` | Check the `x-api-key` header. |
| 402 | `insufficient_credits` | [Add credits](https://onekey.dev/pricing); your balance must cover the price. |
| 404 | `not_found` | Unknown endpoint path. |
| 422 | `invalid_params` | Fix the parameters using the table above. Free. |
| 429 | `rate_limited` | Wait `Retry-After` seconds, then retry. |
| 502 | `upstream_error` | The source failed. Refunded; retry with backoff. |

See [Errors](https://onekey.dev/docs/errors.md) for the full list and retry guidance.

Status: stable (verified against the live source).