TL;DR An LNURLcash bearer note is a 32 byte secret. Whoever holds the string holds the money. That makes it the cleanest allowance I have found for an autonomous agent: hand it a note worth 100 sats and it cannot spend 101, because the bound is the asset rather than a policy you hope something enforces. What you can actually do with it. Sell API calls for a twentieth of a penny , to callers who never sign up for anything. Thirty lines in front of your existing API, about fifteen ...