# React

> Source: `src/content/docs/clients/react.mdx`
> Canonical URL: https://rivet.dev/docs/clients/react
> Description: Connect React apps to Rivet Actors.

---
## Getting Started

See the [React quickstart guide](/docs/actors/quickstart/react) for getting started.

## Install

## Minimal Client

```tsx Counter.tsx
import { createRivetKit } from "@rivetkit/react";
import type { registry } from "./index";

const { useActor } = createRivetKit<typeof registry>({
  endpoint: "https://my-namespace:pk_...@api.rivet.dev",
});

function Counter() {
  const { connection, connStatus } = useActor({ name: "counter", key: ["my-counter"] });

  if (connStatus !== "connected" || !connection) return <div>Connecting...</div>;
  return <button onClick={() => connection.increment(1)}>+</button>;
}
```

```ts index.ts @hide
import { actor, setup } from "rivetkit";

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

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

registry.start();
```

## Stateless vs Stateful

```tsx
import { createRivetKit } from "@rivetkit/react";

const { useActor } = createRivetKit();

function Counter() {
  const counter = useActor({ name: "counter", key: ["my-counter"] });

  const increment = async () => {
    await counter.connection?.increment(1);
  };

  return <button onClick={increment}>+</button>;
}
```

```tsx
// Stateless: use createClient for one-off calls (SSR or utilities)
import { createClient } from "rivetkit/client";

const client = createClient();
await client.counter.getOrCreate(["my-counter"]).increment(1);
```

## Getting Actors

```tsx
import { createRivetKit } from "@rivetkit/react";
import { createClient } from "rivetkit/client";

const { useActor } = createRivetKit();

function ChatRoom() {
  const room = useActor({ name: "chatRoom", key: ["room-42"] });
  return <div>{room.connStatus}</div>;
}

// For get/getOrCreate/create/getForId, use createClient
const client = createClient();
const handle = 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 handle.resolve();
```

## Connection Parameters

```tsx
import { createRivetKit } from "@rivetkit/react";

const { useActor } = createRivetKit();

function Chat() {
  const chat = useActor({
    name: "chatRoom",
    key: ["general"],
    params: { authToken: "jwt-token-here" },
  });

  return <div>{chat.connStatus}</div>;
}
```

## Subscribing to Events

```tsx
import { createRivetKit } from "@rivetkit/react";

const { useActor } = createRivetKit();

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

  chat.useEvent("message", (msg) => {
    console.log("message:", msg);
  });

  return null;
}
```

## Connection Lifecycle

```tsx
import { createRivetKit } from "@rivetkit/react";

const { useActor } = createRivetKit();

function CounterStatus() {
  const actor = useActor({ name: "counter", key: ["my-counter"] });

  if (actor.connStatus === "connected") {
    console.log("connected");
  }

  if (actor.error) {
    console.error(actor.error);
  }

  return null;
}
```

## Low-Level HTTP & WebSocket

Use the JavaScript client for raw HTTP and WebSocket access:

```tsx @nocheck
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

Use the JavaScript client on your backend (Node.js/Bun). See the [JavaScript client docs](/docs/clients/javascript).

## Error Handling

```tsx
import { ActorError } from "rivetkit/client";
import { createRivetKit } from "@rivetkit/react";

const { useActor } = createRivetKit();

function Profile() {
  const actor = useActor({ name: "user", key: ["user-123"] });

  const updateUsername = async () => {
    try {
      await actor.connection?.updateUsername("ab");
    } catch (error) {
      if (error instanceof ActorError) {
        console.log(error.code, error.metadata);
      }
    }
  };

  return <button onClick={updateUsername}>Update</button>;
}
```

## Concepts

### Keys

Keys uniquely identify actor instances. Use compound keys (arrays) for hierarchical addressing:

```tsx ChatRoom.tsx
import { createRivetKit } from "@rivetkit/react";
import type { registry } from "./index";

const { useActor } = createRivetKit<typeof registry>("http://localhost:6420");

function ChatRoom() {
  const room = useActor({ name: "chatRoom", key: ["org-acme", "general"] });
  return <div>{room.connStatus}</div>;
}
```

```ts index.ts @hide
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 },
});

registry.start();
```

Don't build keys with string interpolation like `"org:${userId}"` when `userId` contains user data. Use arrays instead to prevent key injection attacks.

### Environment Variables

`createRivetKit()` (and the underlying `createClient()` instance) automatically read:

- `RIVET_ENDPOINT`
- `RIVET_NAMESPACE`
- `RIVET_TOKEN`
- `RIVET_RUNNER`

Defaults to `http://localhost:6420` when unset. RivetKit runs on port 6420 by default.

### Endpoint Format

Endpoints support URL auth syntax:

```
https://namespace:token@api.rivet.dev
```

You can also pass the endpoint without auth and provide `RIVET_NAMESPACE` and `RIVET_TOKEN` separately. For serverless deployments, use your app's `/api/rivet` URL. See [Endpoints](/docs/general/endpoints#url-auth-syntax) for details.

## API Reference

**Package:** [@rivetkit/react](https://www.npmjs.com/package/@rivetkit/react)

- [`createRivetKit`](/docs/clients/react) - Create hooks for React
- [`useActor`](/docs/clients/react) - Hook for actor instances

_Source doc path: /docs/clients/react_
