x402 Facilitator

import express from "express";
import { paymentMiddleware, x402ResourceServer } from "@x402/express";
import { ExactEvmScheme } from "@x402/evm/exact/server";
import { HTTPFacilitatorClient } from "@x402/core/server";

const app = express();

const facilitatorClient = new HTTPFacilitatorClient({
  url: "https://facilitator.0xarchive.io",
});

const payTo = "0xYourHyperEvmAddress";

app.use(
  paymentMiddleware(
    {
      "GET /data": {
        accepts: [{
          scheme: "exact",
          price: "$0.001",
          network: "eip155:999",  // HyperEVM
          payTo,
        }],
        description: "Market data endpoint",
        mimeType: "application/json",
      },
    },
    new x402ResourceServer(facilitatorClient)
      .register("eip155:999", new ExactEvmScheme()),
  ),
);

app.get("/data", (req, res) => {
  res.json({ price: 104250.5, symbol: "BTC" });
});

app.listen(4021);

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { ExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const signer = privateKeyToAccount(
  process.env.EVM_PRIVATE_KEY as `0x${string}`,
);

const client = new x402Client();
client.register("eip155:*", new ExactEvmScheme(signer));

const fetchWithPayment = wrapFetchWithPayment(fetch, client);

// Request automatically handles 402 → sign → pay → receive
const response = await fetchWithPayment(
  "https://api.0xarchive.io/v1/hyperliquid/orderbook/BTC",
);

const data = await response.json();
console.log("Orderbook:", data);