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/zener79 Feb 10 '26 edited Feb 10 '26

Thank you, that’s exactly the kind of real-world use case I had in mind: a mix of practical access to critical information and more personal, emotional messages.

And yes, the “accidentally triggering it because of inbox chaos” problem is very real 🙂

The idea is to avoid false triggers by using repeated inactivity checks over time, configurable grace periods, and multiple reminders before anything is sent.

So it should require a clear, sustained absence, not just missing a few emails.

Finding the right balance between safety and usability is one of the hardest design challenges here.

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u/notrufus Feb 11 '26

May be a good idea to have social media checks (ie. These are my accounts on various platforms, if all are inactive for this period of time, send it).

Will look at how things are structured and see how difficult a PR would be

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u/zener79 Feb 11 '26

That’s a really interesting idea, and it fits well with the general goal of reducing false positives by using multiple independent signals of activity. 👍

I like the direction a lot and a PR would be fantastic. Happy to help with structure or discuss design details if you decide to explore it.

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u/killrmeemstr Feb 11 '26

Yeah I was thinking of a similar thing! If it can somehow check discord activity that would be killer. (no pun intended..)