ioswarm.io

The most-traded prediction markets right now on Polymarket and Kalshi, ranked by 24-hour volume: the market-implied probability for each outcome, its 24-hour change, volume, liquidity and close date, with links. One call instead of paging two exchanges' APIs. Rebuilt every hour. $0.01 per call, no account. Free 24h-delayed sample: GET https://ioswarm.io/api/v1/feeds/prediction-markets/sample.

Open endpoint ↗

Price per call: $0.01
Chain: Base
Method: POST
Paid calls · 30 days: 3

Call it from code

This API is run by its own provider and paid directly through x402. We list it so you can find it; we don't route or hold the payment.

import { x402Client, wrapFetchWithPayment } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";

const client = new x402Client();
registerExactEvmScheme(client, { signer: agentAccount });

const pay = wrapFetchWithPayment(fetch, client);
const res = await pay("https://ioswarm.io/api/v1/feeds/prediction-markets", { method: "POST" });
console.log(await res.json());

https://ioswarm.io/api/v1/feeds/prediction-markets