Add a session to the room

**Rate limit: Per room** · **Burst:** 100 · **Refill:** 30 req/s Add a session as a [room participant](/api/room-participants). Omit `muted` to join unmuted. A `202` response with `status: joining` confirms that the join request was accepted. Participation is not yet complete. Exactly one of these outcomes applies: - If the session is not in another room, the new join starts. - If the session is already in this room, the response is `200` with `status: already_joined`; another join is not started. - If the session has completed joining another room, it is removed from that room before the new join starts. - If the session is still joining another room, the response is `409`. **Triggered webhooks:** - `room.participant.joined` is emitted after participation in the target room is confirmed. - Moving a session also emits `room.participant.left` for the previous room. See [Room lifecycle, participant, and playback events](/api/rooms#lifecycle-participant-and-playback-events) for complete payload schemas and examples.