Cross-venue equivalent-market pairs for arbitrage / relative-value spotting. We fuzzy-match open Polymarket vs Kalshi markets by title-token overlap and return candidate pairs with both venues' YES prices and the implied-probability spread (Polymarket YES minus Kalshi YES). Tune with minScore (0-1 title-similarity floor) and limit. Heuristic — a high score is a strong candidate, not a guaranteed identical contract. Read-only, keyless. No public source maps these directly; the pairing is derived by 2s.io.
/api/predict/matched-pairsPAYMENT-SIGNATURE.The matched pairs API is a pay-per-call predict endpoint built for AI agents and autonomous software. Cross-venue equivalent-market pairs for arbitrage / relative-value spotting.
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 matched pairs 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 | Max pairs (default 20). min 1 · max 50 |
minScore | number | Minimum title-similarity score 0-1 (default 0.3). min 0 · max 1 |
# 1. Probe with no auth → 402 envelope with PaymentRequirements curl -sS 'https://2s.io/api/predict/matched-pairs?limit=1&minScore=0' # 2. Sign + retry with PAYMENT-SIGNATURE: curl -sS 'https://2s.io/api/predict/matched-pairs?limit=1&minScore=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/matched-pairs?limit=1&minScore=0'
import { TwoS } from '@2sio/sdk'
const client = new TwoS({
privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})
const result = await client.predict.matchedPairs({
"limit": 1,
"minScore": 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.matched_pairs(limit=1, minScore=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.matched-pairs",
"arguments": {
"limit": 1,
"minScore": 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": [
{
"score": 1,
"polymarket": {
"title": "example",
"yesPrice": 1,
"volumeUsd": 1,
"ref": "example",
"url": "example"
},
"kalshi": {
"title": "example",
"yesPrice": 1,
"volumeUsd": 1,
"ref": "example",
"url": "example"
},
"yesSpread": 1
}
],
"total": 1,
"source": {
"provider": "example",
"url": "example",
"license": "example"
},
"meta": {
"count": 1,
"note": "example"
}
}