React SDK

Peer dependency: React 18 or newer.

@flagfix/react wraps @flagfix/browser with a provider and hooks. Install @flagfix/react only; it pulls the browser package. Use a client key and the same apiHost as the browser SDK.

import { FlagFixProvider, useHasFeature, useTrack } from "@flagfix/react";

export function App({ serverFlagState }) {
  return (
    <FlagFixProvider
      options={{
        clientKey: process.env.NEXT_PUBLIC_FLAGFIX_CLIENT_KEY!,
        apiHost:
          process.env.NEXT_PUBLIC_FLAGFIX_API_HOST ??
          "https://api.flagfix.io",
      }}
      serverFlagState={serverFlagState}
    >
      <Checkout />
    </FlagFixProvider>
  );
}

Hook	Behavior
`useFlagFix()`	`{ client, status, startup, serverFlagState }`
`useSdkStatus()`	`idle`, `starting`, `ready`, `failed`
`useFlagFixClient()`	Throws outside the provider
`useFlags()` / `useFlag(key)`	Subscribed snapshot, SSR-safe
`useFlagMeta()` / `useFlagState()`	Version and full state
`useHasFeature(key, fallback?)`	Boolean. Fallback defaults to false. No exposure
`useTrack()`	Before start, returns `queued: false` and `reason: "NOT_STARTED"`

Pass client when you create it outside render. ownLifecycle then defaults to false, so unmount does not call shutdown. serverFlagState is the first paint and avoids a flash.