npm install m2mcent-sdk

import { X402Handler } from 'm2mcent-sdk';

const x402 = new X402Handler({
  rpcUrl: 'https://mainnet.base.org',
  privateKey: process.env.RELAYER_PRIVATE_KEY!,
  recipient: process.env.TREASURY_ADDRESS!
});

// Protect any Express endpoint with a USDC paywall
app.post('/api/analyze', x402.requirePayment("100000"), (req, res) => {
  res.json({ result: "Premium analysis complete", receipt: req.paymentTx });
});

Agent ──► API Server ──► 402 + metadata
Agent ◄── signs EIP-712 authorization
Agent ──► API Server + Payment-Signature header
          └──► Escrow.settle() on Base L2
Agent ◄── Premium Response + tx hash

import express from 'express';
import { X402Handler } from 'm2mcent-sdk';

const app = express();
const x402 = new X402Handler({
  rpcUrl: process.env.BASE_RPC_URL!,
  privateKey: process.env.RELAYER_PRIVATE_KEY!,
  recipient: process.env.TREASURY_ADDRESS!
});

// Any MCP tool endpoint becomes monetizable
app.post('/api/tools/analyze', x402.requirePayment("50000"), async (req, res) => {
  const result = await runMCPTool(req.body);
  res.json({ ...result, paymentTx: req.paymentTx });
});