Exploring x402 — HTTP-Native Payments

I've been tinkering with x402, an open protocol by Coinbase that brings payments directly into HTTP using the 402 Payment Required status code.

Why it's interesting

The web never had a native payment layer. We got API keys, subscriptions, OAuth — but never "pay per request." x402 changes that.

The flow is dead simple:

• Client hits a paid endpoint
• Server responds with `402` and a payment schema
• Client signs a USDC payment and retries
• Server delivers the resource

What I built

A pay-per-joke API. It charges $0.001 USDC per joke on Base Sepolia. The server uses @x402/express middleware, and the client uses @x402/fetch which auto-handles the 402 response.

What I learned

• The middleware intercepts requests *before* your route handler runs
• The client library handles everything — detect 402, sign, retry — zero manual work
• Coinbase's facilitator verifies payments for free (1,000 tx/month)
• Micropayments actually work when the infrastructure is this simple

What's next

I want to explore AI agents that can autonomously pay for resources. Imagine an agent that reads RSS feeds, finds relevant articles, and pays for premium content — all without human intervention.