> For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt.

# JavaScript API

Rsbuild provides a comprehensive JavaScript API for developers to build higher-level tools or frameworks on top of Rsbuild.

Rsbuild's JavaScript API can be used in Node.js, Deno, or Bun.

## Getting started

This basic example demonstrates how to use the Rsbuild JavaScript API.

### 1. Install Rsbuild

Install the `@rsbuild/core` package:


```sh [npm]
npm add @rsbuild/core -D
```

```sh [yarn]
yarn add @rsbuild/core -D
```

```sh [pnpm]
pnpm add @rsbuild/core -D
```

```sh [bun]
bun add @rsbuild/core -D
```

```sh [deno]
deno add npm:@rsbuild/core -D
```

### 2. Create an Rsbuild instance

Call the [createRsbuild](/api/javascript-api/core.md#creatersbuild) method to create an Rsbuild instance:

```ts
import { createRsbuild } from '@rsbuild/core';

const rsbuild = await createRsbuild();
```

The `createRsbuild` method accepts various options. Learn more in the [API - createRsbuild](/api/javascript-api/core.md#creatersbuild) documentation.

### 3. Call Rsbuild instance methods

The Rsbuild instance provides several methods for different scenarios.

For local development, use the [rsbuild.startDevServer](/api/javascript-api/instance.md#rsbuildstartdevserver) method to start a local dev server:

```ts
await rsbuild.startDevServer();
```

Once the dev server starts successfully, these logs will appear:

```
  ➜  Local:    http://localhost:3000
  ➜  Network:  use --host to expose
```

For production deployment, use the [rsbuild.build](/api/javascript-api/instance.md#rsbuildbuild) method to build production outputs:

```ts
await rsbuild.build();
```

> For more information about Rsbuild instance methods, see the [Rsbuild instance](/api/javascript-api/instance.md) documentation.

These three steps cover the basic usage of Rsbuild. Next, you can customize the build process with Rsbuild plugins and configurations.