# simplex smp relay
If you haven’t run into it before: SimpleX Chat is an open-source private messenger, roughly the same kind of thing as Signal. It does the normal messenger things: one-to-one and group chats, audio and video calls, and file sharing. It has apps for phones and desktops. The interesting part is not so much what the app can do, but how the network underneath it works.
SimpleX does not give you an identity on a server. Instead, SMP relays provide one-way message queues that temporarily hold encrypted messages until the recipient collects them. That makes relays replaceable infrastructure rather than the home of your account.
I run a public SMP relay at smp.salix.host. The same relay is also available as an onion service, and the server address below includes both routes. You can use the regular hostname directly or reach it over Tor without maintaining two separate entries.
Use the add relay button below to pass the address to SimpleX Chat. If your browser does not open the app, copy the complete address into the SMP-server section of SimpleX’s network settings:
smp://CLSyD_x8NphQoqd_c6kmrxrvyOoKKXCdyFG0INCNE2A=:U9ekvtT2oC1luEKyzk12NVcj3XdgqZyPOhD1zY1BwAk=@smp.salix.host,salixhostbpuc7m6tvamfzffwynpzvonkyuo22nkf6ov5pondh2h24ad.onion:5223You do not need a salix.host account, and you can keep other SMP relays configured alongside this one. The relay only carries encrypted queues: it cannot read your messages, but a relay can still observe connection timing and, over the regular hostname, the IP address connecting to it. Use the onion route with Tor if hiding that network metadata matters to you.
This is a personally operated service with no SLA. I keep it maintained and available, but you should configure more than one relay rather than making any single server a point of failure.
~$