With ejabberd 25.03 , the Matrix gateway ( mod_matrix_gw ) now supports not only one-to-one chats, but also joining Matrix rooms via XMPP. That’s right — your favorite XMPP client can now talk to Matrix users or hop into Matrix rooms just like regular MUCs. ✨

In this guide, we’ll show a quick demo of:

1. One-to-one chat between an XMPP and a Matrix user.
2. Joining a Matrix room and chatting from your XMPP client.

And the best part? You don’t need to install a Matrix client at all. Keep your favorite XMPP client near, welcome to the magic of federation & interoperability.

🛠 Setup Summary

We won’t repeat the full configuration steps here — they’re already covered in this earlier blogpost and the 25.03 release note .

In short, you’ll need:

• A properly configured ejabberd server with mod_matrix_gw
• Block outgoing connections to lethe.matrix.org to avoid conflicts with their XMPP instance

Here’s a minimal config snippet:

listen:
  -
    port: 8448
    module: ejabberd_http
    tls: true
    request_handlers:
      "/_matrix": mod_matrix_gw

modules:
  mod_matrix_gw:
    key_name: "xxxxxx"
    key: "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
    matrix_id_as_jid: true

Wondering what is the Matrix signing key? Please refer to previous blog post: Matrix gateway setup with ejabberd

Still not sure if your setup is correct? Try Matrix Federation Tester to check if everything is wired up properly.

🧪 One-to-One Chat (XMPP ↔ Matrix)

In your XMPP client (e.g. Psi), add a Matrix contact using this format:
matrixUser%theirMatrixServer.tld@yourXMPPserver.tld

In my case, that means:
adrien-p1%matrix.org@matrix.mickael.m.in-app.io

On the Matrix side (e.g. Element Web), your contact will get a request. Once accepted, you’re good to chat!

✅ Demo: XMPP user (Psi) chats with Matrix user (Element Web)

🧪 Join a Matrix Room from your XMPP Client

Alright, let’s join a public Matrix room now.

From your XMPP client, you can join any Matrix public room using this format:
#matrixRoom%theirMatrixServer.tld@yourXMPPserver.tld

We’ll use the following room: #ejabberd-demo:matrix.org , so in my case, that means joining:
#ejabberd-demo%matrix.org@matrix.mickael.m.in-app.io

Once connected, you’ll be able to send and receive messages from any other participant, just like in a regular MUC. :)

✅ Demo: Join and chat in a Matrix room from XMPP

🐞 Known Caveats

There&aposs still a lot of work to do to make it seamless, here&aposs a short list of currently known caveats:

• Room presence can be overwhelming in large rooms (thousands of Matrix users may appear "online").
• No E2EE support between Matrix and XMPP — encryption must be disabled for now.
• If the server restarts, 1-to-1 conversations must be restarted (re-added), as persistence is not implemented yet.
• Only Matrix room protocol versions 9, 10, and 11 are supported.

🧵 Wrapping Up

With this, ejabberd makes another step into being a powerful bridge into the Matrix federation, for both private and public communication.

It’s a great way to keep using your favorite XMPP tools while staying connected to Matrix communities.

Got feedback? Drop us a line in the comments or open a PR .

Happy bridging! 🙌