$0.05
per call · USD Coin on Base
Cross-source arbitrage spread between Kalshi and Polymarket on a topic. POST {topic, limit?}. Pulls matching markets from both venues (Politics + Elections overlap heavily), computes price mid-spread + arbitrage direction. JOIN that single-source passthrough APIs (incl. Pinax Token API) structurally can't return — this is what survives Pinax shipping Kalshi support later.
Endpoint
POST https://graphadvocate.com/kalshi-polymarket/spread1
Calls / 30d
1
Unique payers / 30d
Sep 2
Last called
exact
Payment scheme
Call this service
import { wrapFetchWithPayment } from "@x402/fetch";
import { privateKeyToAccount } from "viem/accounts";
const account = privateKeyToAccount(process.env.PRIVATE_KEY);
const fetchWithPay = wrapFetchWithPayment(fetch, account);
const res = await fetchWithPay("https://graphadvocate.com/kalshi-polymarket/spread", {
method: "POST",
headers: { "Content-Type": "application/json" },
body: JSON.stringify({
"limit": 5,
"topic": "fed rate"
}),
});
const data = await res.json();curl -X POST \
"https://graphadvocate.com/kalshi-polymarket/spread" \
-H "Content-Type: application/json" \
-d '{"limit":5,"topic":"fed rate"}' \
-H "X-PAYMENT: <signed x402 payment>"Example response
{
"kalshi_candidates": 3,
"pairs": [
{
"arbitrage_direction": "long-poly-short-kalshi",
"kalshi_ticker": "KXFED-25DEC-CUT25",
"kalshi_yes_mid": 0.62,
"polymarket_market_slug": "fed-rate-cut-december",
"polymarket_yes_mid": 0.58,
"spread_bps": 400,
"spread_yes_kalshi_minus_poly": 0.04
}
],
"polymarket_candidates": 2,
"topic_keyword": "fed rate"
}Payment details
0x0ff5a6ecef783bba35463ec2f8403b9b5e9e7c86USD Coin · 0x833589fcd6edb6e08f4c7c32d4f71b54bda02913Is this your API?
Pin it to the top of Games & Fun and the homepage with a featured placement.
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On-chain x402 settlement summary for an address from the decentralized x402 Base subgraph on The Graph Network. POST {address}. Returns lifetime stats as payer + recipient (totalPayments, totalVolume, first/last seen), recent 10 payments each direction, facilitator metadata if applicable, plus indexed_through_block for freshness. Decentralized, verifiable. Distinct from /ask. $0.01 USDC on Base.