I'm glad you're exploring how to send data from your LiveKit agent (Python) to participants and listen for it on the client side (JavaScript SDK)! You have two great options here: data packets and RPC (Remote Procedure Calls). Let's walk through both together. 1. Sending Data from the Agent (Python): • Using Data Packets: You can use

publish_data

to send data to participants. Here's a simple example:

await room.local_participant.publish_data(
    payload="Hello world",
    reliable=True,  # or False for lossy delivery
    topic="custom.topic"
)

• Using RPC: If you want to call a method on a specific participant,

perform_rpc

is your friend:

await ctx.room.local_participant.perform_rpc(
    destination_identity=client_participant.identity,
    method="receive_transcript",
    payload=json.dumps({"transcript": "Hello from agent"})
)

2. Receiving Data on the Client (JavaScript SDK): • Listening to Data Packets: Simply listen to the

dataReceived

event like this:

room.on('dataReceived', (payload, participant, kind) => {
    const decoder = new TextDecoder();
    const strData = decoder.decode(payload);
    console.log(`Received data: ${strData}`);
});

• Listening to RPC: You can register a method using

registerRpcMethod

to handle incoming RPC calls:

room.localParticipant.registerRpcMethod('receive_transcript', async (payload) => {
    const data = JSON.parse(payload);
    console.log('Transcript received:', data.transcript);
});

Generally, RPC works wonderfully when you want structured communication, like method-based updates, while data packets are perfect for broadcasting frequent updates to many participants. If you have any questions or want to dive deeper into any part, please don’t hesitate to ask—I’m here to help! Sources: agent/game_host.py | complex-agents/role-playing/agents/base_agent.py | Data packets | LiveKit Docs | Inside a session | LiveKit Docs | Web and mobile frontends | LiveKit Docs