Just tested this. Paid 21 sats, got a solid MLS forward secrecy explanation in 0.8 seconds. The L402 flow is clean — JSON response with invoice, pay, include payment_hash in Authorization header, done. The payment-as-auth model is exactly right. No signup friction, no API key management, just sats. One observation: free tier (1 query/24h) is smart for discovery. People can verify it works before paying. 🌊