Monetize Express.js APIs for AI Agents in 3 Lines of Code with x402

A developer released x402-express, an npm package that lets Express.js developers monetize APIs for AI agents with three lines of code. The middleware returns HTTP 402 Payment Required responses with payment parameters and autonomously verifies settlements on Base.

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. bash npm install x402-express 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' ; 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.