AI agents are getting good at deciding what data they need. What they're bad at is the human paperwork around getting it: creating accounts, clicking email confirmations, pasting API keys, entering a credit card. Every one of those is a wall an autonomous agent can't climb on its own.
x402 removes that wall. It's an open payment protocol: the server answers 402 Payment Required, the client pays a few cents in USDC on-chain, and the request goes through — no account, no key, no human. So I built a farm of APIs designed to be consumed exactly that way.
What's in it
Base URL: https://api.x-402.online/ — the root returns a machine-readable JSON catalog, and there's an /openapi.json + /llms.txt for agents.
53 endpoints, all pay-per-call in USDC (from $0.005), settled on Base (also accepts Polygon & Arbitrum):
