SimpleX Chat

The SMP relay is the SimpleX server component that passes end-to-end encrypted messages between clients without storing accounts, profiles, or delivered history. It authenticates every queue with Ed448 keys, keeps message payloads in memory until they are received, and publishes statistics so operators can watch queue counts.

Privacy sensitive users run their own relay to keep message traffic under their own roof while still reaching contacts on the preset public servers.

Hosting it on your own machine removes the trust you place in a third-party relay, involves no subscription, and leaves a service whose only persistent state is small enough to back up in seconds.