RivetKit JavaScript Client

First Steps

1. Install the client (latest: 2.0.42) npm install rivetkit@2.0.42
2. Create a client with createClient() and call actor actions.

Getting Started

Minimal Client

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import { createClient } from "rivetkit/client";
import type { registry } from "./registry";

const client = createClient<typeof registry>({
  endpoint: "https://my-namespace:pk_...@api.rivet.dev",
});
const counter = client.counter.getOrCreate(["my-counter"]);
const count = await counter.increment(1);

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import { actor, setup } from "rivetkit";

export const counter = actor({
  state: { count: 0 },
  actions: {
    increment: (c, x: number) => {
      c.state.count += x;
      return c.state.count;
    },
  },
});

export const registry = setup({
  use: { counter },
});
`## Stateless vs Stateful`
import { createClient } from "rivetkit/client";

const client = createClient();
const handle = client.counter.getOrCreate(["my-counter"]);

// Stateless: each call is independent
await handle.increment(1);

// Stateful: keep a connection open for realtime events
const conn = handle.connect();
conn.on("count", (value: number) => console.log(value));
await conn.increment(1);
`## Getting Actors`
import { createClient } from "rivetkit/client";

const client = createClient();
const room = client.chatRoom.getOrCreate(["room-42"]);
const existing = client.chatRoom.get(["room-42"]);

const created = await client.game.create(["game-1"], {
  input: { mode: "ranked" },
});

const byId = client.chatRoom.getForId("actor-id");
const resolvedId = await room.resolve();
`## Connection Parameters`
import { createClient } from "rivetkit/client";

const client = createClient();
const chat = client.chatRoom.getOrCreate(["general"], {
  params: { authToken: "jwt-token-here" },
});

const conn = chat.connect();
`## Subscribing to Events`
import { createClient } from "rivetkit/client";

const client = createClient();
const conn = client.chatRoom.getOrCreate(["general"]).connect();
conn.on("message", (msg: string) => console.log(msg));
conn.once("gameOver", () => console.log("done"));
`## Connection Lifecycle`
import { createClient } from "rivetkit/client";

const client = createClient();
const conn = client.chatRoom.getOrCreate(["general"]).connect();

conn.onOpen(() => console.log("connected"));
conn.onClose(() => console.log("disconnected"));
conn.onError((err) => console.error("error:", err));
conn.onStatusChange((status) => console.log("status:", status));

await conn.dispose();

Low-Level HTTP & WebSocket

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import { createClient } from "rivetkit/client";

const client = createClient();
const handle = client.chatRoom.getOrCreate(["general"]);

const response = await handle.fetch("history");
const history = await response.json();

const ws = await handle.websocket("stream");
ws.addEventListener("message", (event) => {
  console.log("message:", event.data);
});
ws.send("hello");
`## Calling from Backend`
import { Hono } from "hono";
import { createClient } from "rivetkit/client";

const app = new Hono();
const client = createClient();

app.post("/increment/:name", async (c) => {
  const counterHandle = client.counter.getOrCreate([c.req.param("name")]);
  const newCount = await counterHandle.increment(1);
  return c.json({ count: newCount });
});
`## Error Handling`
import { ActorError } from "rivetkit/client";
import { createClient } from "rivetkit/client";

const client = createClient();

try {
  await client.user.getOrCreate(["user-123"]).updateUsername("ab");
} catch (error) {
  if (error instanceof ActorError) {
    console.log(error.code, error.metadata);
  }
}

Concepts

Keys

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import { createClient } from "rivetkit/client";
import type { registry } from "./registry";

const client = createClient<typeof registry>();

// Compound key: [org, room]
client.chatRoom.getOrCreate(["org-acme", "general"]);

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import { actor, setup } from "rivetkit";

export const chatRoom = actor({
  state: { messages: [] as string[] },
  actions: {
    getRoomInfo: (c) => ({ org: c.key[0], room: c.key[1] }),
  },
});

export const registry = setup({
  use: { chatRoom },
});

Environment Variables

• RIVET_ENDPOINT (endpoint)
• RIVET_NAMESPACE
• RIVET_TOKEN
• RIVET_RUNNER

Endpoint Format

API Reference

• LHOST_PH_23 - Create a client
• LHOST_PH_24 - Engine driver
• LHOST_PH_25 - Driver configuration
• LHOST_PH_26 - Client type

Need More Than the Client?