featbit-node-server-sdk

# FeatBit Node.js Server SDK

Expert guidance for integrating FeatBit Server-Side SDK in Node.js backend applications.

> **📦 Official SDK**: [@featbit/node-server-sdk](https://www.npmjs.com/package/@featbit/node-server-sdk)  
> **📖 Full Documentation**: [GitHub Repository](https://github.com/featbit/featbit-node-server-sdk)

⚠️ **Important**: This is a **server-side SDK** for multi-user systems (web servers, APIs). Not for browser/client-side applications.

## Quick Start

### Installation

```bash
npm install --save @featbit/node-server-sdk
```

### Prerequisites

Before using the SDK, obtain:
- **Environment Secret (SDK Key)**: [How to get](https://docs.featbit.co/sdk/faq#how-to-get-the-environment-secret)
- **SDK URLs**: [How to get](https://docs.featbit.co/sdk/faq#how-to-get-the-sdk-urls)
  - FeatBit SaaS: `wss://app-eval.featbit.co` and `https://app-eval.featbit.co`
  - Self-hosted: `ws://localhost:5100` and `http://localhost:5100`

### Basic Usage

```javascript
import { FbClientBuilder, UserBuilder } from "@featbit/node-server-sdk";

// Setup SDK options
const fbClient = new FbClientBuilder()
    .sdkKey("your_sdk_key")
    .streamingUri('wss://app-eval.featbit.co')
    .eventsUri("https://app-eval.featbit.co")
    .build();

(async () => {
  // Wait for the SDK to be initialized
  try {
    await fbClient.waitForInitialization();
  } catch(err) {
    // failed to initialize the SDK
    console.log(err);
  }

  // flag to be evaluated
  const flagKey = "game-runner";
  
  // create a user
  const user = new UserBuilder('a-unique-key-of-user')
    .name('bob')
    .custom('sex', 'female')
    .custom('age', 18)
    .build();

  // evaluate a feature flag for a given user
  const boolVariation = await fbClient.boolVariation(flagKey, user, false);
  console.log(`flag '${flagKey}' returns ${boolVariation} for user ${user.Key}`);

  // evaluate a boolean flag for a given user with evaluation detail
  const boolVariationDetail = await fbClient.boolVariationDetai