zopu-code/.agents/skills/ai-agent/reference/actors/events.md

Realtime

Source: src/content/docs/actors/events.mdx Canonical URL: https://rivet.dev/docs/actors/events Description: Events enable realtime communication from actors to clients. While clients use actions to send data to actors, events allow actors to push updates to connected clients instantly.

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Events can be sent to clients connected using .connect(). They have no effect on low-level WebSocket connections.

For worked realtime patterns, see the cookbook: Live Cursors and Presence and Chat Room.

Publishing Events from Actors

Broadcasting to All Clients

Define event names and payload types with events and event(), then use c.broadcast(eventName, ...args) to send events to all connected clients:

Sending to Specific Connections

Send events to individual connections using conn.send(eventName, ...args):

Send events to all connections except the sender:

Subscribing to Events from Clients

Clients must establish a connection to receive events from actors. Use .connect() to create a persistent connection, then listen for events.

Basic Event Subscription

Use connection.on(eventName, callback) to listen for events:

import { useState } from "react";
import { useActor } from "./rivetkit";

function ChatRoom() {
  const [messages, setMessages] = useState<Array<{id: string, userId: string, text: string}>>([]);

  const chatRoom = useActor({
    name: "chatRoom",
    key: ["general"]
  });

  // Listen for events
  chatRoom.useEvent("messageReceived", (message) => {
    setMessages(prev => [...prev, message]);
  });

  // ...rest of component...
}

One-time Event Listeners

Use connection.once(eventName, callback) for events that should only trigger once:

import { useState, useEffect } from "react";
import { useActor } from "./rivetkit";

function GameLobby() {
  const [gameStarted, setGameStarted] = useState(false);

  const gameRoom = useActor({
    name: "gameRoom",
    key: ["room-456"],
    params: {
      playerId: "player-789",
      role: "player"
    }
  });

  // Listen for game start (only once)
  useEffect(() => {
    if (!gameRoom.connection) return;

    const handleGameStart = () => {
      console.log('Game has started!');
      setGameStarted(true);
    };

    gameRoom.connection.once('gameStarted', handleGameStart);
  }, [gameRoom.connection]);

  // ...rest of component...
}

Removing Event Listeners

Use the callback returned from .on() to remove event listeners:

import { useState, useEffect } from "react";
import { useActor } from "./rivetkit";

function ConditionalListener() {
  const [isListening, setIsListening] = useState(false);
  const [messages, setMessages] = useState<string[]>([]);

  const chatRoom = useActor({
    name: "chatRoom",
    key: ["general"]
  });

  useEffect(() => {
    if (!chatRoom.connection || !isListening) return;

    // Add listener
    const unsubscribe = chatRoom.connection.on('messageReceived', (message) => {
      setMessages(prev => [...prev, message.text]);
    });

    // Cleanup - remove listener when component unmounts or listening stops
    return () => {
      unsubscribe();
    };
  }, [chatRoom.connection, isListening]);

  // ...rest of component...
}

Debugging

• GET /inspector/connections shows active connections and connection metadata.
• Use this to confirm clients are connected before expecting broadcasts.
• GET /inspector/summary provides connections, RPCs, and queue size in one response.
• In non-dev mode, inspector endpoints require authorization.

More About Connections

For more details on actor connections, including connection lifecycle, authentication, and advanced connection patterns, see the Connections documentation.

API Reference

• RivetEvent - Base event interface
• RivetMessageEvent - Message event type
• RivetCloseEvent - Close event type
• UniversalEvent - Universal event type
• UniversalMessageEvent - Universal message event
• UniversalErrorEvent - Universal error event
• EventUnsubscribe - Unsubscribe function type

Source doc path: /docs/actors/events