FeatBit React Client SDK

When to Use This Skill

Use for client-side React applications (React 16.3+) that evaluate feature flags in the browser.

Why client SDK: Connects directly from the browser via WebSocket, syncs flag data for the current user, and evaluates flags locally. No backend proxy is required.

Do not use for React Native (use the React Native SDK), Next.js server-side rendering, or any server-side context — use @featbit/node-server-sdk for server-side Next.js instead.

Source

https://github.com/featbit/featbit-react-client-sdk

Setup Workflow

Copy and track progress:

Step 1: Install the package
Step 2: Wrap the app root with the provider
Step 3: Consume feature flags in a component

Step 1: Install the package

Run:

npm install @featbit/react-client-sdk

Step 2: Wrap the app root with the provider

Use asyncWithFbProvider at the app entry point before rendering so flags are ready at startup:

import { createRoot } from 'react-dom/client';
import { asyncWithFbProvider } from '@featbit/react-client-sdk';

(async () => {
  const config = {
    options: {
      sdkKey: 'YOUR ENVIRONMENT SECRET',
      streamingUrl: 'THE STREAMING URL',
      eventsUrl: 'THE EVENTS URL',
      user: {
        id: 'user-key-123',
        userName: 'Jane',
        customizedProperties: []
      }
    }
  };

  const FbProvider = await asyncWithFbProvider(config);
  const root = createRoot(document.getElementById('root'));
  root.render(
    <FbProvider>
      <App />
    </FbProvider>
  );
})();

Why asyncWithFbProvider: Awaiting initialization prevents flag flicker — the provider resolves before the first render. Use withFbProvider only if you prefer to render first and apply flag updates after.

Step 3: Consume flags in a component

import { useFlags } from '@featbit/react-client-sdk';

function MyComponent() {
  const { 'game-enabled': gameEnabled } = useFlags();
  return gameEnabled ? <Game /> : <div>Feature not available</div>;
}

If flags return fallback values unexpectedly, verify sdkKey, streamingUrl, and eventsUrl.

Feature Flag Evaluation

import { useFlags, useFbClient } from '@featbit/react-client-sdk';

const MyComponent = props => {
  const fbClient = useFbClient();
  const { flag1, flag2 } = useFlags();

  // Or access all flags by key:
  // const flags = useFlags();
  // flags['game-enabled']  // bracket notation required for keys with dashes
  // flags.flag1            // dot notation works for simple alphanumeric keys

  return (
    <div>
      <div>flag1: {flag1}</div>
      <div>flag2: {flag2}</div>
    </div>
  );
};

useFlags() returns all flags. Destructure for known keys or access by bracket/dot notation. Use useFbClient() to get the underlying JavaScript SDK client (e.g., to call await fbClient.identify(user) after login).

Class components — two options:

withFbConsumer: wraps the component and injects flags and fbClient as props
static contextType = context: assign context from the SDK and access this.context.flags

User Custom Properties

React SDK users pass custom properties as a customizedProperties array of {name, value} objects. Add an entry for each attribute referenced in targeting rules:

const config = {
  options: {
    sdkKey: 'YOUR ENVIRONMENT SECRET',
    streamingUrl: 'THE STREAMING URL',
    eventsUrl: 'THE EVENTS URL',
    user: {
      id: 'user-key-123',
      userName: 'Jane',
      customizedProperties: [
        { name: 'age', value: '25' },
        { name: 'country', value: 'FR' },
        { name: 'plan', value: 'premium' }
      ]
    }
  }
};

To update the user after login, call await fbClient.identify(user) with the same shape. See Switch user after initialization.