matrix-bot/docs/jitsi.md

# Jitsi in Riot

Riot uses [Jitsi](https://jitsi.org/) for conference calls, which provides options for
self-hosting your own server and supports most major platforms.

1:1 calls, or calls between you and one other person, do not use Jitsi. Instead, those
calls work directly between clients or via TURN servers configured on the respective 
homeservers.

There's a number of ways to start a Jitsi call: the easiest way is to click on the 
voice or video buttons near the message composer in a room with more than 2 people. This
will add a Jitsi widget which allows anyone in the room to join.

Integration managers (available through the 4 squares in the top right of the room) may
provide their own approaches for adding Jitsi widgets.

## Configuring Riot to use your self-hosted Jitsi server

Riot will use the Jitsi server that is embedded in the widget, even if it is not the
one you configured. This is because conference calls must be held on a single Jitsi
server and cannot be split over multiple servers.

However, you can configure Riot to *start* a conference with your Jitsi server by adding
to your [config](./config.md) the following:
```json
{
  "jitsi": {
    "preferredDomain": "your.jitsi.example.org"
  }
}
```

The default is `jitsi.riot.im` (a free service offered by Riot), and the demo site for
Jitsi uses `meet.jit.si` (also free).

Once you've applied the config change, refresh Riot and press the call button. This
should start a new conference on your Jitsi server. 

**Note**: The widget URL will point to a `jitsi.html` page hosted by Riot. The Jitsi
domain will appear later in the URL as a configuration parameter.

## Mobile app support

Currently the Riot mobile apps do not support custom Jitsi servers and will instead
use the default `jitsi.riot.im` server. When users on the mobile apps join the call,
they will be joining a different conference which has the same name, but not the same
participants. This is a known bug and which needs to be fixed.