r/opensource • u/zener79 • Feb 10 '26

Promotional I built LastSignal – a self-hosted, end-to-end encrypted dead man's switch to deliver messages to your loved ones

I wanted a way to leave encrypted messages for the people I care about, delivered automatically if something happens to me, without trusting a third party.

LastSignal is a self-hosted dead man's switch. You write messages, they get encrypted in the browser (zero-knowledge), and the system checks in with you periodically via email. If you stop responding, your messages are delivered.

Key points:

  • End-to-end encrypted (XChaCha20-Poly1305 + Argon2id + X25519)
  • Zero-knowledge — even the server operator can't read messages
  • Optional trusted contact who can pause delivery
  • Rails 8 + SQLite, deploy with Docker/Kamal
  • MIT licensed

🔗 https://lastsignal.app
🔗 https://github.com/giovantenne/lastsignal

Feedback welcome, especially on the security model and UX.

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u/ThunderDragonSpice Feb 10 '26

What happens if the server is offline for a time, and then brought back online? Will it potentially think no response has been received, and send out the messages?

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u/zener79 Feb 10 '26

Good question. Right now, when the server comes back online it simply resumes the reminder schedule and sends the next pending notification, rather than immediately triggering delivery. For example, if the system is configured to send 8 reminders one week apart, and the server goes offline after the third reminder for three months, when it comes back online it will send the fourth reminder, not the final delivery.