Polymarket whale radar: the largest recent trades by USD notional across all markets, ranked. Optional minUsd floor and limit. Each entry includes wallet, trader name, market, side, outcome, size, price, USD value, and tx hash — for tracking smart-money / large positioning. Read-only from Polymarket's Data API.
/api/predict/whalesPAYMENT-SIGNATURE.The whales API is a pay-per-call predict endpoint built for AI agents and autonomous software. Polymarket whale radar: the largest recent trades by USD notional across all markets, ranked.
There is no signup and no API key. An agent (or any HTTP client) hits the endpoint, receives an x402 "402 Payment Required" challenge, signs a sub-cent USDC payment on Base or Solana, and retries — the data comes back on the paid request. That makes it a drop-in whales data source for an agent tool-use loop, an MCP host, or a backend that needs predict data on demand without onboarding to yet another vendor portal.
| Name | Type | Description |
|---|---|---|
limit | integer | min 1 · max 100 |
minUsd | number | Only trades at/above this USD notional. min 0 |
# 1. Probe with no auth → 402 envelope with PaymentRequirements curl -sS 'https://2s.io/api/predict/whales?limit=1&minUsd=0' # 2. Sign + retry with PAYMENT-SIGNATURE: curl -sS 'https://2s.io/api/predict/whales?limit=1&minUsd=0' \ -H 'PAYMENT-SIGNATURE: <base64-json-payload>' # Or use the canonical runner (handles probe → sign → retry): # EVM_PRIVATE_KEY=0x... node --env-file=.env.local \ # --experimental-strip-types scripts/x402-pay.ts \ # 'https://2s.io/api/predict/whales?limit=1&minUsd=0'
import { TwoS } from '@2sio/sdk'
const client = new TwoS({
privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})
const result = await client.predict.whales({
"limit": 1,
"minUsd": 0
})
console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)import os
from twosio import TwoS
client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])
result = client.predict.whales(limit=1, minUsd=0)
print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)// 1. Add @2sio/mcp to your MCP host config (Claude Desktop example below).
// EVM_PRIVATE_KEY funds x402 payments per call.
// claude_desktop_config.json
{
"mcpServers": {
"2sio": {
"command": "npx",
"args": ["-y", "@2sio/mcp"],
"env": { "EVM_PRIVATE_KEY": "0x..." }
}
}
}
// 2. Once the server is running, agents call this tool via standard MCP:
{
"jsonrpc": "2.0",
"id": 1,
"method": "tools/call",
"params": {
"name": "predict.whales",
"arguments": {
"limit": 1,
"minUsd": 0
}
}
}| Field | Type | Description |
|---|---|---|
ok | boolean | one of: true |
items | array | |
total | integer | Total matching rows upstream; null when unknown. |
source | object | |
meta | object |
{
"ok": true,
"items": [
{
"wallet": "example",
"name": "example",
"side": "example",
"outcome": "example",
"size": 1,
"price": 1,
"usd": 1,
"timestamp": 1,
"title": "example",
"slug": "example",
"conditionId": "example",
"txHash": "example"
}
],
"total": 1,
"source": {
"provider": "example",
"url": "example",
"license": "example"
},
"meta": {
"count": 1
}
}