1\. Install the SDK
```sh
npm install unleash-client
```

2\. Initialize Unleash
```js
const { initialize } = require('unleash-client');

const unleash = initialize({
  url: '<YOUR_API_URL>',
  appName: 'unleash-onboarding-node',
  customHeaders: { Authorization: '<YOUR_API_TOKEN>' },
  metricsInterval: 5000,
});
```

3\. Check feature flag status
```js
setInterval(() => {
  console.log('Is enabled', unleash.isEnabled('<YOUR_FLAG>'));
}, 1000);
```

---
```js
const { UnleashClient } = require('unleash-proxy-client');

const unleash = new UnleashClient({
  url: '<YOUR_API_URL>',
  appName: 'unleash-onboarding-node',
  customHeaders: { Authorization: process.env.UNLEASH_API_KEY  },
});

unleash.start();
```

---
- [SDK repository with documentation](https://github.com/Unleash/unleash-client-node)
- [Node.js SDK example with CodeSandbox](https://github.com/Unleash/unleash-sdk-examples/tree/main/JavaScript)
- [Node.js SDK tutorial](https://dev.to/reeshee/how-to-implement-feature-flags-in-nodejs-using-unleash-3907)