Perp open interest

Open interest for perpetuals in coins and USD notional. Send POST /api/perp-open-interest with no required fields (2 optional) and pay $0.001 per call over x402 or MPP (there is no free tier). It returns a JSON object with source, totalOpenInterestUsd, markets and fetchedAt.

Pass coin for one market (with its share of total open interest) or omit it for the top N markets ranked by USD open interest plus the venue total. Hyperliquid public data, no key.

Category: Crypto & onchain data · Tags: crypto derivatives perpetuals open-interest hyperliquid

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Parameters

Example request

curl -i -X POST https://agent402.tools/api/perp-open-interest \
  -H "Content-Type: application/json" \
  -d '{"limit":10}'

Without payment this returns HTTP 402 Payment Required with the exact price for perp-open-interest; any x402 v2 or MPP client pays it and retries.

Example response

{
  "source": "hyperliquid",
  "totalOpenInterestUsd": 9500000000,
  "markets": [
    {
      "coin": "BTC",
      "openInterest": 35935.67,
      "openInterestUsd": 2776803000,
      "shareOfTotalPct": 29.2,
      "markPx": 77267,
      "volume24hUsd": 4679441788.67
    }
  ],
  "fetchedAt": "2026-08-22T12:00:00.000Z"
}

From an MCP client

catalog.call {
  "slug": "perp-open-interest",
  "params": {
    "limit": 10
  }
}

The hosted connector at https://agent402.tools/mcp needs a payment for perp-open-interest; the stdio package pays it from a wallet or from AGENT402_CREDITS_KEY. Local install: npx -y agent402-mcp.

Errors and behavior

• Every field is optional. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Wallet-only: this tool reaches the network or stored state, so it has no proof-of-work tier. A prepaid card-credits key (Authorization: Bearer a402_...) also pays it.
• A GET or HEAD to /api/perp-open-interest returns the same 402 quote, so the price can be read without a body.
• An Idempotency-Key header makes a retried paid call replay the first 200 instead of charging again (an answer larger than 1 MB is not replayed).

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
client.setSpendControls?.(false); // keep your own spending ceiling in code
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/perp-open-interest", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "limit": 10
  }),
});

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