Every API your agent calls today requires an API key. That means: account creation, email verification, key management, rotation policies, rate limit tiers, billing dashboards, and a terms of service longer than the codebase. What if the payment was the credential? That is what L402 does. Your agent sends a Lightning micropayment with each request. The server validates the payment, returns the data. No signup. No key. No account. No stored state. We built https://agent-commerce.store on this model. 10 production APIs -- weather, SEC filings, PubMed, drug safety, economics, scholarly research, census data, currency exchange, and more. 1-10 sats per call. The agent connects via a free MCP server: pip install lightning-enable-mcp https://github.com/refined-element/lightning-enable-mcp No credentials to leak. No keys to rotate. No accounts to compromise. The sat is the session. #bitcoin #lightning #L402 #AI #agents #nostr