A single Polymarket market by conditionId, slug, or id. Returns the question, outcomes + live prices (implied probabilities), CLOB token ids, USD volume + liquidity, dates, description, and URL. Pass one of conditionId / slug / id.
/api/predict/marketPAYMENT-SIGNATURE.The market API is a pay-per-call predict endpoint built for AI agents and autonomous software. A single Polymarket market by conditionId, slug, or id.
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 market 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 |
|---|---|---|
conditionId | string | max 80 chars |
slug | string | max 200 chars |
id | string | max 40 chars |
# 1. Probe with no auth → 402 envelope with PaymentRequirements curl -sS 'https://2s.io/api/predict/market?conditionId=example&slug=example&id=example' # 2. Sign + retry with PAYMENT-SIGNATURE: curl -sS 'https://2s.io/api/predict/market?conditionId=example&slug=example&id=example' \ -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/market?conditionId=example&slug=example&id=example'
import { TwoS } from '@2sio/sdk'
const client = new TwoS({
privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})
const result = await client.predict.market({
"conditionId": "example",
"slug": "example",
"id": "example"
})
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.market(conditionId="example", slug="example", id="example")
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.market",
"arguments": {
"conditionId": "example",
"slug": "example",
"id": "example"
}
}
}| Field | Type | Description |
|---|---|---|
ok | boolean | one of: true |
items | array | |
total | integer | Total matching rows upstream; null when unknown. |
source | object |
{
"ok": true,
"items": [
{
"id": "example",
"question": "example",
"slug": "example",
"conditionId": "example",
"outcomes": [
"example"
],
"outcomePrices": [
1
],
"clobTokenIds": [
"example"
],
"volumeUsd": 1,
"liquidityUsd": 1,
"active": false,
"closed": false,
"startDate": "example",
"endDate": "example",
"description": "example",
"url": "example"
}
],
"total": 1,
"source": {
"provider": "example",
"url": "example",
"license": "example"
}
}