Fetch Client

npm install @sei-js/x402-fetch viem dotenv

import { config } from "dotenv";
import { Hex } from "viem";
import { privateKeyToAccount } from "viem/accounts";
import {
  wrapFetchWithPayment,
  decodeXPaymentResponse,
} from "@sei-js/x402-fetch";

config();

const privateKey = process.env.PRIVATE_KEY as Hex;
const baseURL = process.env.RESOURCE_SERVER_URL as string; // e.g. http://localhost:4021
const endpointPath = process.env.ENDPOINT_PATH as string; // e.g. /weather
const url = `${baseURL}${endpointPath}`;

if (!baseURL || !privateKey || !endpointPath) {
  console.error("Missing required environment variables");
  process.exit(1);
}

// Create account from private key
const account = privateKeyToAccount(privateKey);

// Wrap fetch with payment handling
const fetchWithPayment = wrapFetchWithPayment(fetch, account);

// Make a paid request
fetchWithPayment(url, {
  method: "GET",
})
  .then(async (response) => {
    const body = await response.json();
    console.log("Response:", body);

    // Decode the payment response
    const paymentResponse = decodeXPaymentResponse(
      response.headers.get("x-payment-response")!
    );
    console.log("Payment details:", paymentResponse);
  })
  .catch((error) => {
    console.error("Error:", error.response?.data?.error);
  });

# Required: Your private key for making payments
PRIVATE_KEY=0xYourPrivateKeyHere

# Required: The server URL hosting the paid API
RESOURCE_SERVER_URL=http://localhost:4021

# Required: The endpoint path to access
ENDPOINT_PATH=/weather