To check that both a LiveKit room and its data channel are active and open before sending data, you should verify two conditions in your code: 1. Room connection state: Confirm the room is connected. 2. Data channel state: Confirm the relevant data channel is in the

open

state. Here are examples for several SDKs: • *Swift:*`let isRoomConnected = room.connectionState == .connected let isDataChannelOpen = room.publisherDataChannel.isOpen if isRoomConnected && isDataChannelOpen { // Safe to send data }` • *JavaScript:*`const isRoomConnected = room.connectionState === 'connected'; const isDataChannelReady = engine.dataChannelForKind(kind)?.readyState === 'open'; if (isRoomConnected && isDataChannelReady) { // Safe to send data }` • *Android:*`val isRoomConnected = room.connectionState == ConnectionState.CONNECTED val dataChannel = engine.dataChannelForKind(kind) val isDataChannelOpen = dataChannel?.state() == DataChannel.State.OPEN if (isRoomConnected && isDataChannelOpen) { // Safe to send data }` • *Flutter:*`final isRoomConnected = room.connectionState == ConnectionState.connected; final dataChannel = engine._publisherDataChannel(reliability); final isDataChannelOpen = dataChannel?.state == RTCDataChannelState.RTCDataChannelOpen; if (isRoomConnected && isDataChannelOpen) { // Safe to send data }` • *Rust:*`let is_room_connected = room.connection_state() == ConnectionState::Connected; let data_channel = session.data_channel(SignalTarget::Publisher, kind); let is_data_channel_open = data_channel.map(|dc| dc.state() == DataChannelState::Open).unwrap_or(false); if is_room_connected && is_data_channel_open { // Safe to send data }` Best practice: Always check both states before sending data, as the connection process may leave them in different states temporarily. Many SDKs also provide methods like

ensurePublisherConnected

to handle readiness checking automatically. Sources: Sources/LiveKit/Core/Room.swift | src/room/RTCEngine.ts | livekit-android-sdk/src/main/java/io/livekit/android/audio/PreconnectAudioB... | lib/src/core/engine.dart | livekit-ffi/src/server/room.rs | Web and mobile frontends | LiveKit Docs