In LiveKit, participants can register and call RPC (Remote Procedure Call) methods to enable communication between each other. Here's how it works: Registering an RPC Method A participant can register an RPC method using the

registerRpcMethod

function. For example:

room.localParticipant?.registerRpcMethod(
  'greet',  // method name
  async (data: RpcInvocationData) => {
    console.log(`Received greeting from ${data.callerIdentity}: ${data.payload}`);
    return `Hello, ${data.callerIdentity}!`;
  },
);

The handler receives the payload and a

responseTimeout

parameter, which indicates the maximum time available to return a response. Calling an RPC Method To call an RPC method on another participant, use the

performRpc

function. For example:

try {
  const response = await room.localParticipant!.performRpc({
    destinationIdentity: 'recipient-identity',
    method: 'greet',
    payload: 'Hello from RPC!',
  });
  console.log('RPC response:', response);
} catch (error) {
  console.error('RPC call failed:', error);
}

You can also adjust the

responseTimeout

parameter to specify how long to wait for a response. Error Handling In RPC method handlers, you can throw errors of type

RpcError

with a string message, which will be received by the caller. Other error types will result in a generic "1500" ("Application Error"). If you have further questions or need additional clarification, feel free to ask! Sources: LiveKit JS Client SDK - v2.8.1