> ## Documentation Index
> Fetch the complete documentation index at: https://docs.layercode.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Node.js Backend SDK

> API reference for the Layercode Node.js Backend SDK.

<Icon icon="github" size={18} color="black" /> [layercode-node-server-sdk](https://github.com/layercodedev/layercode-node-server-sdk).

## Introduction

The Layercode Node.js Backend SDK provides a simple way to handle the Layercode webhook in your backend. In particular, it makes it easy to return SSE events in the Layercode webhook response format. It supports all popular JavaScript runtime environments, including Node.js, Bun, and Cloudflare Workers.

## Installation

```bash theme={null}
npm install @layercode/node-server-sdk
```

## Usage

```typescript theme={null}
import { streamResponse } from "@layercode/node-server-sdk";

//... inside your webhook request handler ...
return streamResponse(request, async ({ stream }) => {
  stream.tts("Hi, how can I help you today?"); // This text will be sent to Layercode, converted to speech and spoken to the user
  // Call stream.tts() as many times as you need to send multiple pieces of speech to the user
  stream.end(); // This closes the stream and must be called at the end of your response
});
// ...
```

## Reference

### streamResponse

The `streamResponse` function is the main entry point for the SDK. It takes the request body (from the Layercode webhook request) and a handler function as arguments. The handler function receives a `stream` object that can be used to send SSE events to the client.

```typescript theme={null}
function streamResponse(requestBody: Record<string, any>, handler: StreamResponseHandler): Response;
```

#### Parameters

* `requestBody`: The request body from the client. See [Webhook Request Payload](/api-reference/webhook-sse-api#webhook-request-payload).
* `handler`: An async function that receives a `stream` object.

#### Stream Methods

* `stream.tts(content: string)`: Sends a text to be spoken to the user (tts stands for text-to-speech).
* `stream.data(content: any)`: Sends any arbitrary data to the frontend client. Use this for updating your frontend UI.
* `stream.end()`: Closes the stream. Must be called at the end of your response.