Start with x402

import { x402Client, x402HTTPClient } from "@x402/core/client";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";

// Setup wallet
const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`);

// Create x402 client
const evmScheme = new ExactEvmScheme(account);
const coreClient = new x402Client().register("eip155:*", evmScheme);
const httpClient = new x402HTTPClient(coreClient);

// Access paywalled resource
async function accessResource(url: string) {
  try {
    const response = await fetch(url);
    
    if (response.status === 402) {
      // Get payment requirements
      const responseBody = await response.json();
      const paymentRequired = httpClient.getPaymentRequiredResponse(
        (name) => response.headers.get(name),
        responseBody
      );
      
      // Create payment payload
      const paymentPayload = await httpClient.createPaymentPayload(paymentRequired);
      const paymentHeaders = httpClient.encodePaymentSignatureHeader(paymentPayload);
      
      // Retry with payment
      const paidResponse = await fetch(url, {
        headers: { ...paymentHeaders }
      });
      
      if (!paidResponse.ok) {
        throw new Error(`Request failed: ${paidResponse.status}`);
      }
      
      return paidResponse.json();
    }
    
    if (!response.ok) {
      throw new Error(`Request failed: ${response.status}`);
    }
    
    return response.json();
  } catch (error) {
    console.error("Error accessing resource:", error);
    throw error;
  }
}

// Agent pays for weather data automatically
const weatherData = await agent.accessResource("https://api.example.com/weather");

// Protect your AI endpoint with x402
app.get("/ai/analyze", paymentMiddleware, async (c) => {
  const result = await model.analyze(c.req.query);
  return c.json(result);
});

// Agent A requests work from Agent B, pays automatically
const result = await agentA.requestWork(agentB.endpoint, taskData);