Each machine gets an ed25519 keypair on first run. pineotter pair prints a pairing code; approve it on the server side and the host is trusted from then on.
Concurrent edits to the same note produce a .conflict copy next to the newest version. Nothing is ever deleted silently.
# sync every 10 minutes via cron */10 * * * * pineotter push --quiet
Any static file server or small reverse proxy works. The store is a flat directory; back it up with rsync like any other folder.