Self-host the relay

The relay is deliberately small and stateless. Running your own means your traffic never touches ours — and the page you are reading is served by the relay itself, so you can see what you would be running.

One command

git clone https://github.com/FluffyHorizon1/z-messanger
cd z-messanger/server
docker compose up -d

Then in the app: Settings → Developer mode → relay address, and enter wss://your-host. Anyone you talk to needs to be reachable through the same relay, so point your contacts at it too.

What it needs

Node 20+ or Docker, and a TLS certificate for a public deployment.
Memory proportional to queued mail, not to your history: nothing is stored, and queues expire.
No database. No disk. There is nothing to back up, which is the point.

Worth knowing

Queued mail lives in RAM and expires after QUEUE_TTL_HOURS (72 by default), per envelope. A restart drops it — the relay's own restart on a single instance, or the shared store's where several instances coordinate through one (render.ha.yaml), which is why a relay redeploy there no longer loses what is in flight.
Rate limits and queue caps are environment variables, so a small host stays bounded under load.
/health reports liveness and /metrics exposes aggregate delivery counters only — no per-user data.
Multiple instances can share presence through Redis if you need more than one.

Z is source-available, not open source: personal self-hosting is expressly permitted, and commercial use or redistribution needs written permission. The licence is in the repository.