> ## Documentation Index
> Fetch the complete documentation index at: https://goldrush.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# perpsAtOpenInterestCap | Hyperliquid Info API

> Hyperliquid perpsAtOpenInterestCap: list the perp assets currently at their open-interest cap.

<CardGroup cols={2}>
  <Card title="Credit Cost"> 1 per call</Card>
  <Card title="Processing"> Realtime</Card>
</CardGroup>

The Hyperliquid info endpoint with `type: "perpsAtOpenInterestCap"` is used to list the perp assets currently at their open-interest cap.

<Tip>
  Estimate your monthly cost for this API using the [Pricing Calculator](/docs/pricing-calculator?endpoint=%2Fapi-reference%2Fhyperliquid-info%2Fperps-at-open-interest-cap).
</Tip>

<Info>
  * Wire-equal to `POST api.hyperliquid.xyz/info` with `{"type": "perpsAtOpenInterestCap"}`.
  * While an asset is in this list it has reached its open-interest cap; orders that would increase aggregate open interest are rejected (see the `openInterestCap*` order-rejection reasons) until open interest falls back below the cap.
  * This is a global, non-user-keyed type refreshed continuously from upstream Hyperliquid.
</Info>

Returns the list of perpetual assets that are currently at their open-interest cap, as an array of coin symbol strings. Use it to detect which markets are constrained before placing orders that would add open interest.

## Endpoint

```
POST https://hypercore.goldrushdata.com/info
Authorization: Bearer <GOLDRUSH_API_KEY>
Content-Type: application/json
```

## Request

<ParamField body="type" type="string" required>
  Always `"perpsAtOpenInterestCap"`.
</ParamField>

### Example

<CodeGroup>
  ```bash cURL theme={null}
  curl -X POST https://hypercore.goldrushdata.com/info \
    -H "Authorization: Bearer $GOLDRUSH_API_KEY" \
    -H "Content-Type: application/json" \
    -d '{
      "type": "perpsAtOpenInterestCap"
    }'
  ```

  ```typescript TypeScript theme={null}
  const response = await fetch("https://hypercore.goldrushdata.com/info", {
    method: "POST",
    headers: {
      "Authorization": `Bearer ${process.env.GOLDRUSH_API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      type: "perpsAtOpenInterestCap",
    }),
  });

  const cappedPerps = await response.json();
  ```

  ```python Python theme={null}
  import os, requests

  response = requests.post(
      "https://hypercore.goldrushdata.com/info",
      headers={"Authorization": f"Bearer {os.environ['GOLDRUSH_API_KEY']}"},
      json={"type": "perpsAtOpenInterestCap"},
  )

  capped_perps = response.json()
  ```
</CodeGroup>

## Response

An array of coin symbol strings for the perp assets currently at their open-interest cap. Empty when no market is capped.

```json theme={null}
["CANTO", "FTM", "JELLY", "LOOM", "RLB", "ZEREBRO"]
```

### Field descriptions

<ResponseField name="[n]" type="string">
  Coin symbol of a perp asset currently at its open-interest cap.
</ResponseField>

*Last reviewed: 2026-07-24*