HTTP 402: Teaching the Web to Pay Agents

For thirty years, one HTTP status code has sat unused in the spec: 402, "Payment Required." As AI agents become real economic actors that browse, decide, and transact on our behalf, that gap suddenly matters. Agents can't hold a credit card, pass a captcha, or click through a checkout, so the payment rails we built for humans break down. This talk looks at x402, an open and chain-agnostic standard that finally activates HTTP 402 for machine-native payments, and walks through how it actually works: the request, 402, pay, and retry loop, the facilitator pattern, and what it takes to charge an agent a fraction of a cent for an API call, data, or similar. From there, we get to the hard part: what a settlement layer for autonomous agents must guarantee, including predictable sub-cent fees, fast deterministic finality, neutral open infrastructure, and a tamper-evident record of every payment. We'll make that concrete on Hedera, using its fixed low fees and fast finality for the payments themselves, its native token service for stablecoin transfers, and its consensus service as a verifiable audit log of agent activity. You'll leave with a clear architecture for agentic commerce and an open standard you can start designing against today.