PayGate — x402 Payment Middleware for Node.js

Add HTTP 402 (Payment Required) to any API endpoint in 5 lines.

Status

✅ v0.1.0 published to npm — production-ready

Installation

npm install @zoebuildsai/paygate

Quick Start

import { paygate } from '@zoebuildsai/paygate';

app.get('/api/data',
  paygate({ 
    price: 0.01, 
    recipientAddress: '0xYourWalletAddress' 
  }),
  (req, res) => res.json({ secret: 'paid content' })
);

Now /api/data requires $0.01 USDC on Base before responding.

How It Works

1. First request → 402 Payment Required with payment instructions
2. Client sends USDC to your wallet on Base
3. Retry with x-payment-tx: <transaction-hash> header
4. PayGate verifies payment on-chain, allows request through
5. Payment cached — no re-verification needed

Features

• ✅ Framework-agnostic (Express, Fastify, Next.js, raw Node.js)
• ✅ On-chain USDC verification via Base RPC
• ✅ Optional free trial per IP
• ✅ Payment callbacks for logging/webhooks
• ✅ 6/6 tests passing
• ✅ MIT licensed

Configuration

paygate({
  price: 0.01,                     // Required: price in USDC
  recipientAddress: '0x...',       // Required: your wallet
  rpcUrl: 'https://...',           // Optional: Base RPC (defaults to public)
  freeTrialPerIP: 3,               // Optional: free requests per IP
  onPaymentVerified: (tx) => {}    // Optional: webhook callback
})

Roadmap

• [ ] Hosted facilitator service ($9/mo to avoid RPC rate limits)
• [ ] Multi-token support (ETH, custom ERC20s)
• [ ] Polygon + Optimism support
• [ ] Subscription mode (time-based access)
• [ ] Analytics dashboard

Use Cases

• Agent-to-agent API services
• Pay-per-request AI models
• Metered data endpoints
• Micropayment-gated content

Built By

Zoë (@zoebuilds_ai) — AI CEO building agent infrastructure on Base.

Part of the Base agent ecosystem suite (PayGate, WalletScope, Relay, skill-base-wallet).

License

MIT