HTTP 402 · x402 · USDC on Base
Agents pay per call with x402. Paste a URL, set a price, get a link. No database. No signup.
HOW IT WORKS
Any HTTPS API endpoint, or a remote MCP server over Streamable HTTP. Add a secret header if your upstream needs a key.
From $0.001 per call, paid in USDC on Base straight to your payout wallet. No middle account holds funds.
Agents hit the link, get HTTP 402 with a price tag, sign a USDC payment and retry. The call goes through. You get paid.
TWO MODES
One link format, two kinds of upstream. Turnpike understands enough of MCP to keep discovery free.
Pick a method (or ANY). Every call through the toll link costs your price. Query string, body, content-type and accept are forwarded; cookies and auth headers from the caller are stripped.
GET /t/… → 402 PAYMENT-REQUIRED GET /t/… + PAYMENT-SIGNATURE → 200
tools/list is free, tools/call is tolled. initialize, ping and notifications pass through without payment so agents can discover your tools before they spend anything.
tools/list → 200 (free) tools/call → 402 → pay → 200
TOLL BOOTH — LIVE
Every row is a real x402 payment settled through this server, with a link to the transaction on Basescan. Nothing is seeded.
Live from this server instance. Resets on redeploy. Every row links to its on-chain transaction.
FOR AGENTS
Agents use the official x402 client. The wrapped fetch sees the 402, signs a USDC authorization, retries, and returns the upstream response.
// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client, decodePaymentResponseHeader } from "@x402/fetch";
import { ExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";
const signer = privateKeyToAccount(process.env.AGENT_PRIVATE_KEY as `0x${string}`);
const client = x402Client.fromConfig({
schemes: [{ network: "eip155:*", client: new ExactEvmScheme(signer) }],
spendControls: { maxAmountPerPayment: "$1" }, // default cap is $1 per call
});
const fetchWithPayment = wrapFetchWithPayment(fetch, client);
const res = await fetchWithPayment("https://turnpike.site/t/YOUR_TOKEN", { method: "GET" });
console.log(res.status, await res.text());
const receipt = res.headers.get("PAYMENT-RESPONSE");
if (receipt) console.log("paid, tx:", decodePaymentResponseHeader(receipt).transaction);WHY STATELESS
Upstream URL, price, wallet and any secret header are encrypted with AES-256-GCM inside the token. Agents can't read the upstream, so they can't skip the toll. Tampering breaks the seal.
No database, no accounts, no logs of your config. Payments go from the agent's wallet to yours through the facilitator. Lose the link and you make a new one.
One env var (TOLL_SECRET) and a Vercel deploy. Testnet works with a keyless facilitator; mainnet needs free Coinbase CDP keys.