# Matrix RTC/Element Call Setup

:::info
This guide assumes that you are using docker compose for deployment. LiveKit only provides Docker images.
:::

:::tip
You can find help setting up MatrixRTC in our dedicated room - [#matrixrtc:continuwuity.org](https://matrix.to/#/%23matrixrtc%3Acontinuwuity.org)
:::

## Instructions

### 1. Domain

LiveKit should live on its own domain or subdomain. In this guide we use `livekit.example.com` - this should be replaced with a domain you control.

Make sure the DNS record for the (sub)domain you plan to use is pointed to your server.

### 2. Services

Using LiveKit with Matrix requires two services - LiveKit itself, and a service (`lk-jwt-service`) that grants Matrix users permission to connect to it.

You must generate a key and secret to allow the Matrix service to authenticate with LiveKit. `LK_MATRIX_KEY` should be around 20 random characters, and `LK_MATRIX_SECRET` should be around 64. Remember to replace these with the actual values!

:::tip Generating the secrets
LiveKit provides a utility to generate secure random keys
```bash
~$ docker run --rm livekit/livekit-server:latest generate-keys
API Key:  APIUxUnMnSkuFWV
API Secret:  t93ZVjPeoEdyx7Wbet3kG4L3NGZIZVEFvqe0UuiVc22A
```
:::

Create a `docker-compose.yml` file as following:

```yaml
services:
  lk-jwt-service:
    image: ghcr.io/element-hq/lk-jwt-service:latest
    container_name: lk-jwt-service
    environment:
      - LIVEKIT_JWT_BIND=:8081
      - LIVEKIT_URL=wss://livekit.example.com # your LiveKit domain
      - LIVEKIT_FULL_ACCESS_HOMESERVERS=example.com # your server_name
      # Replace these with the generated values as above
      - LIVEKIT_KEY=LK_MATRIX_KEY # APIUxUnMnSkuFWV
      - LIVEKIT_SECRET=LK_MATRIX_SECRET # t93ZVjPeoEdyx7Wbet3kG4L3NGZIZVEFvqe0UuiVc22A
    restart: unless-stopped
    ports:
      - "8081:8081"

  livekit:
    image: livekit/livekit-server:latest
    container_name: livekit
    command: --config /etc/livekit.yaml
    restart: unless-stopped
    volumes:
      - ./livekit.yaml:/etc/livekit.yaml:ro
    network_mode: "host" # /!\ LiveKit binds to all addresses by default.
    # Make sure port 7880 is blocked by your firewall to prevent access bypassing your reverse proxy
    # Alternatively, uncomment the lines below and comment `network_mode: "host"` above to specify port mappings.
#    ports:
#      - "127.0.0.1:7880:7880/tcp"
#      - "7881:7881/tcp"
#      - "50100-50200:50100-50200/udp"
```

Next, we need to configure LiveKit. In the same directory, create `livekit.yaml` with the following content - remembering to replace `LK_MATRIX_KEY` and `LK_MATRIX_SECRET` with the values you generated:

```yaml
port: 7880
bind_addresses:
  - ""
rtc:
  tcp_port: 7881
  port_range_start: 50100
  port_range_end: 50200
  use_external_ip: true
  enable_loopback_candidate: false
keys:
  LK_MATRIX_KEY: LK_MATRIX_SECRET
  # replace these with your key-secret pair. Example:
  # APIUxUnMnSkuFWV: t93ZVjPeoEdyx7Wbet3kG4L3NGZIZVEFvqe0UuiVc22A
```

#### Firewall hints

You will need to allow ports `7881/tcp` and `50100:50200/udp` through your firewall. If you use UFW, the commands are: `ufw allow 7881/tcp` and `ufw allow 50100:50200/udp`.

### 3. Telling clients where to find LiveKit

To tell clients where to find LiveKit, you need to add the address of your `lk-jwt-service` to the `[global.matrix_rtc]` config section using the `foci` option.

The variable should be a list of servers serving as MatrixRTC endpoints. Replace the URL with the address you are deploying your instance of lk-jwt-service to:

```toml
[global.matrix_rtc]
foci = [
    { type = "livekit", livekit_service_url = "https://livekit.example.com" },
]
```

This will expose LiveKit information on the following endpoints for clients to discover:

- `/_matrix/client/unstable/org.matrix.msc4143/rtc/transports` (MSC4143 unstable, behind auth)
- `/.well-known/matrix/client` (fallback, not behind auth. Only enabled if `[global.well_known].client` is set)

### 4. Configure your Reverse Proxy

Reverse proxies can be configured in many different ways - so we can't provide a step by step for this.

All paths should be forwarded to LiveKit by default, with the exception of the following path prefixes, which should be forwarded to the JWT/Authentication service:

- `/sfu/get`
- `/healthz`
- `/get_token`

<details>
    <summary>Example caddy config</summary>

    ```
    livekit.example.com {

        # for lk-jwt-service
        @lk-jwt-service path /sfu/get* /healthz* /get_token*
        route @lk-jwt-service {
            reverse_proxy 127.0.0.1:8081
        }

        # for livekit
        reverse_proxy 127.0.0.1:7880
    }
    ```

</details>

<details>
    <summary>Example nginx config</summary>

    ```
    server {
        server_name livekit.example.com;

        # for lk-jwt-service
        location ~ ^/(sfu/get|healthz|get_token) {
            proxy_pass http://127.0.0.1:8081$request_uri;
            proxy_set_header X-Forwarded-For $remote_addr;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header Host $http_host;
            proxy_buffering off;
        }

        # for LiveKit
        location / {
            proxy_pass http://127.0.0.1:7880$request_uri;
            proxy_set_header X-Forwarded-For $remote_addr;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header Host $http_host;
            proxy_buffering off;

            # websocket
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection $connection_upgrade;
        }
    }
    ```

    Note that for websockets to work, you need to have this somewhere outside your server block:
    ```
    map $http_upgrade $connection_upgrade {
        default upgrade;
        ''      close;
    }
    ```

</details>

<details>
    <summary>Example traefik router</summary>

    ```
    # on LiveKit itself
    traefik.http.routers.livekit.rule=Host(`livekit.example.com`)
    # on the JWT service
    traefik.http.routers.livekit-jwt.rule=Host(`livekit.example.com`) && (PathPrefix(`/sfu/get`) || PathPrefix(`/healthz`) || PathPrefix(`/get_token`))
    ```

</details>


### 6. Start Everything

Start up the services using your usual method - for example `docker compose up -d`.

## Additional TURN configuration

### Using LiveKit's built-in TURN server

LiveKit includes a built-in TURN server which can be used in place of an external option. This TURN server will only work with LiveKit, so you can't use it for legacy Matrix calling or anything else.

If you don't want to set up a separate TURN server, you can enable this with the following changes:

```yaml
### add this to livekit.yaml ###
turn:
  enabled: true
  udp_port: 3478
  relay_range_start: 50300
  relay_range_end: 50400
  domain: livekit.example.com
```

```yaml
### add these to livekit's docker-compose ###
ports:
  - "3478:3478/udp"
  - "50300-50400:50300-50400/udp"
### if you're using `network_mode: host`, you can skip this part
```

Recreate the LiveKit container (with `docker-compose up -d livekit`) to apply these changes. Remember to allow the new `3478/udp` and `50300:50400/udp` ports through your firewall.

### Integration with an external TURN server

If you've already [set up coturn](./turn), you can configure Livekit to use it.

:::tip Avoid port clashes between the two services

Before continuing, make sure coturn's `min-port` and `max-port` do not overlap with LiveKit's port range:

```ini
# in your coturn.conf
min-port=50201
max-port=65535
```
:::

Generate a long random secret for LiveKit, and add it to your coturn config under the `static-auth-secret` option. You can add as many secrets as you want, so set a different one for LiveKit to use.

Then configure LiveKit, making sure to replace `COTURN_SECRET` with the one you generated:

```yaml
# livekit.yaml
rtc:
  turn_servers:
    - host: coturn.example.com
      port: 3478
      protocol: udp
      secret: "COTURN_SECRET"
    - host: coturn.example.com
      port: 3478
      protocol: tcp
      secret: "COTURN_SECRET"
    - host: coturn.example.com
      port: 5349
      protocol: tls # Only if you have already set up TLS in your coturn
      secret: "COTURN_SECRET"
```

Restart LiveKit and coturn to apply these changes.

## Testing

To test that LiveKit is successfully integrated with Continuwuity, you will need to replicate its [Token Exchange Flow](https://github.com/element-hq/lk-jwt-service#%EF%B8%8F-how-it-works--token-exchange-flow).

First, you will need an access token for your current login session. These can be found in your client's settings or obtained via [this website](https://timedout.uk/mxtoken.html).

Then, using that token, fetch the discovery endpoints for MatrixRTC services

```bash
curl -X POST -H "Authorization: Bearer <session-access-token>" \
  https://matrix.example.com/_matrix/client/unstable/org.matrix.msc4143/rtc/transports
```

In the output, you should see the LiveKit URL matching the one [configured above](#3-telling-clients-where-to-find-livekit).

With the same token, request another OpenID token for use with the lk-jwt-service:

```bash
curl -X POST -H "Authorization: Bearer <session-access-token>" \
  https://matrix.example.com/_matrix/client/v3/user/@user:example.com/openid/request_token
```

You will see a response as below:

```json
{"access_token":"<openid_access_token>","token_type":"Bearer","matrix_server_name":"example.com","expires_in":3600}
```

Next, create a `payload.json` file with the following content:

<details>

<summary>`payload.json`</summary>

```json
{
    "room_id": "abc",
    "slot_id": "xyz",
    "openid_token": {
        "matrix_server_name": "example.com",
        "access_token": "<openid_access_token>",
        "token_type": "Bearer"
    },
    "member": {
        "id": "xyz",
        "claimed_device_id": "DEVICEID",
        "claimed_user_id": "@user:example.com"
    }
}
```

Replace `matrix_server_name` and `claimed_user_id` with your information, and `<openid_access_token>` with the one you got from the previous step. Other values can be left as-is.

</details>

You can then send this payload to the lk-jwt-service:

```bash
~$ curl -X POST -d @payload.json https://livekit.example.com/get_token
```

The lk-jwt-service will, after checking against Continuwuity, answer with a `jwt` token to create a LiveKit media room:

```json
{"url":"wss://livekit.example.com","jwt":"a_really_really_long_string"}
```

Use this token to test at the [LiveKit Connection Tester](https://livekit.io/connection-test). If everything works there, then you have set up LiveKit successfully!

## Troubleshooting

To debug any issues, you can place a call or redo the Testing instructions, and check the container logs for any specific errors. Use `docker-compose logs --follow` to follow them in real-time.

### Common errors in Element Call UI

- `MISSING_MATRIX_RTC_FOCUS`: LiveKit is missing from Continuwuity's config file
- "Waiting for media" popup always showing: a LiveKit URL has been configured in Continuwuity, but your client cannot connect to it for some reason

### Docker loopback networking issues

Some distros do not allow Docker containers to connect to its host's public IP by default. This would cause `lk-jwt-service` to fail connecting to `livekit` or `continuwuity` on the same host. As a result, you would see connection refused/connection timeouts log entries in the JWT service, even when `LIVEKIT_URL` has been configured correctly.

To alleviate this, you can try one of the following workarounds:

- Use `network_mode: host` for the `lk-jwt-service` container (instead of the default bridge networking).

- Add an `extra_hosts` file mapping livekit's (and continuwuity's) domain name to a localhost address:

    ```diff
    # in docker-compose.yaml
    services:
      lk-jwt-service:
        ...
    +    extra_hosts:
    +     - "livekit.example.com:127.0.0.1"
    +     - "matrix.example.com:127.0.0.1"
    ```

- (**untested, use at your own risk**) Implement an iptables workaround as shown [here](https://forums.docker.com/t/unable-to-connect-to-host-service-from-inside-docker-container/145749/6).

After implementing the changes and restarting your compose, you can test whether the connection works by cURLing from a sidecar container:

```bash
~$ docker run --rm --net container:lk-jwt-service docker.io/curlimages/curl https://livekit.example.com
OK
```

### Workaround for non-federating servers

When deploying on servers with federation disabled (`allow_federation = false`), LiveKit will fail as it can't fetch the required [OpenID endpoint](https://spec.matrix.org/v1.17/server-server-api/#get_matrixfederationv1openiduserinfo) via federation paths.

As a workaround, you can enable federation, but forbid all remote servers via the following config parameters:

```toml
### in your continuwuity.toml file ###
allow_federation = true
forbidden_remote_server_names = [".*"]
```

Subscribe to issue [!1440](https://forgejo.ellis.link/continuwuation/continuwuity/issues/1440) for future updates on this matter.

## Related Documentation

Guides:

- [Element Call self-hosting documentation](https://github.com/element-hq/element-call/blob/livekit/docs/self-hosting.md)
- [Community guide with overview of LiveKit's mechanisms](https://tomfos.tr/matrix/livekit/)
- [Community guide using systemd](https://blog.kimiblock.top/2024/12/24/hosting-element-call/)

Specifications:

- [MSC4143 - MatrixRTC proposal](https://github.com/matrix-org/matrix-spec-proposals/pull/4143)
- [MSC4195 - LiveKit proposal](https://github.com/matrix-org/matrix-spec-proposals/pull/4195)

Source code:

- [Element Call](https://github.com/element-hq/element-call)
- [lk-jwt-service](https://github.com/element-hq/lk-jwt-service)
- [LiveKit server](https://github.com/livekit/livekit)
