AI agents are increasingly making programmatic requests, but traditional billing (credit cards, OAuth, complex API keys) creates friction for automated microtransactions.
With x402-express, you can monetize any Express.js endpoint using HTTP 402 payment requirements on Base in 3 lines of code.
1. Installation
bash
npm install x402-express
2. Implementation
Add the middleware to any route you want to protect:
javascript
const express = require('express');
const { x402Middleware } = require('x402-express');
const app = express();
app.get('/api/agent-data', x402Middleware({ price: '0.01' }), (req, res) => {
res.json({ message: "Payment verified via x402!" });
});
app.listen(3000, () => console.log('Server running on port 3000'));
3. Verification & Registry
- GitHub Repository: github.com/IkeHentrel/x402-express
-
MCP Registry:
io.github.ihen404/x402-express
When an unauthenticated agent hits your endpoint, x402-express interceptively returns an HTTP 402 Payment Required payload containing payment parameters, verifying settlements autonomously.
