How to monetize your AI agent tools with x402 micropayments

If you've built something an AI agent could use — a data feed, a specialized search API, a tool that does one thing well — you've probably noticed there's no obvious way to charge for it. You could build auth, track API keys, send invoices, set up Stripe, handle webhooks. Or you could just not, and let people use it for free. Neither option is great. The payment infrastructure wasn't designed for agents. Agents don't sign up for things. They don't have credit cards. They can't click an OAuth flow. x402 changes that. What x402 actually is HTTP 402 has been a reserved status code since 1991. It means "payment required." Nobody used it because there was no standard way to pay. The x402 spec gives it meaning: when a request hits a protected endpoint, the server returns 402 with a JSON body describing the payment. The agent reads it, signs a USDC microtransaction on Base L2, and retries with an X-PAYMENT header. The server verifies the payment onchain and returns the data. No API keys. No s