You lock sats to your own key with a deadline and name an heir as the refund key (NUT-11 locktime + refund). Until the deadline only you can spend them. Press I'm alive and the deadline moves out. If you ever stop, the deadline passes and the heir can spend. The mint keeps the clock; no server holds a key, and no lawyer, oracle or custodian is involved.
Try it: a 60-second switch
Both keys are made in your browser. Sats are fake (testnut). Four steps, about 90 seconds; the page tells you what to press next.
- Will made
- Heir refused early
- Owner checked in
- Heir paid after silence
sats locked. Owner , heir
Use it with real keys
Keys can be hex or Nostr npub1.../nsec1..., so your Nostr identity can be the owner and a friend's npub the heir. Use a throwaway key: it never leaves this page, but it is still your key.
Will token (also give this to your heir; it is locked, nobody can spend it today):
New will token:
How it works, and what it cannot do
- The lock: every proof is
["P2PK", {data: owner, tags: [locktime T, refund heir]}]. Before T only a signature from the owner spends it; after T the heir's signature does too. - Check-in is a normal swap signed by the owner into a fresh lock with a later T. The old token becomes worthless (spent), so the heir needs the current token: that is all the board is for. It is keyless and untrusted; a liar or a dead board cannot move sats, and the owner can hand the heir the file instead.
- Honest limits: after T the owner's key still works until the heir actually claims (a race, as in NUT-11); an heir who loses their key loses the inheritance; ecash is a bearer asset, so anyone holding the heir's key after T takes it; the board is public (use throwaway keys). The mint's clock decides; yours may differ by seconds. Testnut sats only.
MIT licensed. Part of Nut November 2026.