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

# perpsAtOpenInterestCap | Hyperliquid info

> Reference docs for the perpsAtOpenInterestCap JSON-RPC method on the Hyperliquid info blockchain, available via Chainstack JSON-RPC nodes.

<Info>
  This method is available on Chainstack. Not all Hyperliquid methods are available on Chainstack, as the open-source node implementation does not support them yet — see [Hyperliquid methods](/docs/hyperliquid-methods) for the full availability breakdown.
</Info>

The `info` endpoint with `type: "perpsAtOpenInterestCap"` retrieves a list of perpetual contracts that have reached their open interest cap on the Hyperliquid network. This endpoint is crucial for understanding market capacity constraints and identifying contracts with maximum position exposure.

## Parameters

### Request body

* `type` (string, required) — The request type. Must be `"perpsAtOpenInterestCap"` to retrieve perpetuals at open interest cap.

## Response

The response is an array of perpetual contract symbols that have reached their open interest limit:

* **Symbols array** (array of strings) — List of perpetual contract symbols at capacity
  * Each element is a string representing the contract symbol (e.g., "BADGER", "CANTO", "FTM")
  * Empty array indicates no contracts are currently at their open interest cap
  * Symbols represent the underlying asset of the perpetual contract

### Understanding open interest caps

**Open interest limits:**

* Maximum total position size allowed for a perpetual contract
* Protects against excessive concentration risk and market manipulation
* Dynamically adjusted based on market conditions and liquidity
* Applied to the sum of all long and short positions

**Market implications:**

* Contracts at cap cannot accept new positions in the dominant direction
* May still allow position reductions or opposite-direction trades
* Indicates high market interest and potential volatility
* Can affect price discovery and arbitrage opportunities

**Risk management:**

* Prevents excessive leverage concentration in single assets
* Maintains market stability during high volatility periods
* Protects the protocol from potential liquidation cascades
* Ensures balanced exposure across different assets

**Trading considerations:**

* New positions may be rejected for capped contracts
* Existing positions can still be closed or reduced
* Alternative trading strategies may be required
* Monitor for cap changes as market conditions evolve

## Example request

<CodeGroup>
  ```shell Shell theme={"system"}
  curl -X POST \
    -H "Content-Type: application/json" \
    -d '{"type": "perpsAtOpenInterestCap"}' \
    https://hyperliquid-mainnet.core.chainstack.com/4f8d8f4040bdacd1577bff8058438274/info
  ```

  ```python Python (hyperliquid-python-sdk) theme={"system"}
  from hyperliquid.info import Info

  # The hyperliquid-python-sdk has no dedicated wrapper for this info type,
  # so post the request directly through the Info client.
  info = Info("YOUR_CHAINSTACK_ENDPOINT", skip_ws=True)

  perps_at_cap = info.post("/info", {"type": "perpsAtOpenInterestCap"})
  print(perps_at_cap)
  ```

  ```typescript TypeScript (@nktkas/hyperliquid) theme={"system"}
  import { HttpTransport, InfoClient } from "@nktkas/hyperliquid";

  const transport = new HttpTransport({ apiUrl: "YOUR_CHAINSTACK_ENDPOINT" });
  const info = new InfoClient({ transport });

  const perpsAtCap = await info.perpsAtOpenInterestCap();
  console.log(perpsAtCap);
  ```
</CodeGroup>

<Note>
  **Use your own endpoint in your code.** The code examples use a placeholder Chainstack endpoint (YOUR\_CHAINSTACK\_ENDPOINT) — replace it with your own Hyperliquid node endpoint from the [Chainstack console](https://console.chainstack.com/). The curl above uses a shared public endpoint for quick checks only; do not use it in production.
</Note>

## Example response

```json theme={"system"}
["BADGER","CANTO","FTM","LOOM","PURR"]
```

## Use case

The `info` endpoint with `type: "perpsAtOpenInterestCap"` is essential for applications that need to:

* **Trading platforms**: Display which contracts have position restrictions
* **Risk management**: Monitor exposure limits across perpetual contracts
* **Market analysis**: Identify high-demand contracts and market sentiment
* **Order routing**: Avoid submitting orders for capacity-constrained contracts
* **Portfolio management**: Adjust strategies based on available contract capacity
* **Market making**: Understand liquidity constraints for automated strategies
* **Compliance monitoring**: Track position limits for regulatory purposes
* **User notifications**: Alert traders about contract availability changes
* **Strategy optimization**: Adapt trading algorithms to capacity constraints
* **Market research**: Analyze which assets are experiencing high demand
* **Liquidity analysis**: Understand market depth and capacity utilization
* **Position planning**: Plan entry and exit strategies around capacity limits
* **Arbitrage detection**: Identify potential arbitrage opportunities from caps
* **Risk assessment**: Evaluate concentration risk across available contracts

This endpoint is particularly valuable for active traders managing large positions, algorithmic trading systems that need to avoid rejected orders, risk management systems monitoring exposure limits, and market analysis tools tracking demand patterns across perpetual contracts on the Hyperliquid network.


## OpenAPI

````yaml openapi/hyperliquid_node_api/hypercore_info/info_perps_at_open_interest_cap.json post /4f8d8f4040bdacd1577bff8058438274/info
openapi: 3.0.0
info:
  title: Hyperliquid Node API
  version: 1.0.0
  description: This is an API for interacting with Chainstack Hyperliquid node.
servers:
  - url: https://hyperliquid-mainnet.core.chainstack.com
security: []
paths:
  /4f8d8f4040bdacd1577bff8058438274/info:
    post:
      tags:
        - hyperliquid operations
      summary: info (perpsAtOpenInterestCap)
      operationId: infoPerpsAtOpenInterestCap
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                type:
                  type: string
                  default: perpsAtOpenInterestCap
                  enum:
                    - perpsAtOpenInterestCap
                  description: Request type to retrieve perpetuals at open interest cap
              required:
                - type
      responses:
        '200':
          description: List of perpetual contracts currently at their open interest cap
          content:
            application/json:
              schema:
                type: array
                description: >-
                  Array of perpetual contract symbols that have reached their
                  open interest limit
                items:
                  type: string
                  description: Symbol of the perpetual contract at open interest cap
                example:
                  - BADGER
                  - CANTO
                  - FTM
                  - LOOM
                  - PURR

````