x402 Service Discovery: How Autonomous Agents Find and Pay for APIs at Runtime

x402 Service Discovery: How Autonomous Agents Find and Pay for APIs at Runtime Autonomous agents need to call paid APIs. The problem: there's no standard way to find them. You don't want to hardcode 50 endpoint URLs into your agent. You want it to discover the best available service for any capability at runtime — like DNS for the agent economy. That's what x402 Service Discovery does. What is x402? x402 is a protocol that lets HTTP servers charge for API calls using USDC stablecoin micropayments on Base. A client hits an endpoint, gets a 402 Payment Required response with a payment challenge, pays ~$0.001–$0.05 in USDC, then retries the request with a payment proof header. No API keys, no subscriptions, no billing dashboards. The discovery problem The x402 ecosystem is growing — there are services for research, data feeds, compute, AI agents — but there's no index. You have to know a URL exists before you can call it. We built the missing piece: a service registry where x402-payable A