# Reflag React SDK

React client side library for [Reflag.com](https://reflag.com)

Reflag supports flag toggling, tracking flag usage, [requesting feedback](#userequestfeedback) on features, and [remotely configuring flags](#remote-config).

The Reflag React SDK comes with a [built-in toolbar](https://docs.reflag.com/supported-languages/browser-sdk#toolbar) which appears on `localhost` by default.

## Install

Install via npm:

```shell
npm i @reflag/react-sdk
```

## Get started

### 1. Add the `ReflagProvider` context provider

Add the `ReflagProvider` context provider to your application:

**Example:**

```tsx
import { ReflagProvider } from "@reflag/react-sdk";

<ReflagProvider
  publishableKey="{YOUR_PUBLISHABLE_KEY}"
  context={{
    company: { id: "acme_inc", plan: "pro" },
    user: { id: "john doe" },
  }}
  loadingComponent={<Loading />}
>
  {/* children here are shown when loading finishes or immediately if no `loadingComponent` is given */}
</ReflagProvider>;
```

### 2. Create a new flag and set up type safety

Install the Reflag CLI:

```shell
npm i --save-dev @reflag/cli
```

Run `npx reflag new` to create your first flag!
On the first run, it will sign into Reflag and set up type generation for your project:

```shell
❯ npx reflag new
Opened web browser to facilitate login: https://app.reflag.com/api/oauth/cli/authorize

Welcome to ◪ Reflag!

? Where should we generate the types? gen/flags.d.ts
? What is the output format? react
✔ Configuration created at reflag.config.json.

Creating flag for app Slick app.
? New flag name: Huddle
? New flag key: huddle
✔ Created flag Huddle with key huddle (https://app.reflag.com/features/huddles)
✔ Generated react types in gen/flags.d.ts.
```

> [!Note]
> By default, types will be generated in `gen/flags.d.ts`.
> The default `tsconfig.json` file `include`s this file by default, but if your `tsconfig.json` is different, make sure the file is covered in the `include` property.

### 3. Use `useFlag(<flagKey>)` to get flag status

Using the `useFlag` hook from your components lets you toggle flags on/off and track flag usage:

**Example:**

```tsx
function StartHuddleButton() {
  const {
    isEnabled, // boolean indicating if the flag is enabled
    track, // track usage of the flag
  } = useFlag("huddle");

  if (!isEnabled) {
    return null;
  }

  return <button onClick={track}>Start huddle!</button>;
}
```

`useFlag` can help you do much more. See a full example for `useFlag` [see below](#useflag).

## Setting context

Reflag determines which flags are active for a given `user`, `company`, or `other` context.
You can pass these to the `ReflagProvider` using the `context` prop.

### Using the `context` prop

```tsx
<ReflagProvider
  publishableKey={YOUR_PUBLISHABLE_KEY}
  context={{
    user: { id: "user_123", name: "John Doe", email: "john@acme.com" },
    company: { id: "company_123", name: "Acme, Inc" },
    other: { source: "web" },
  }}
>
  <LoadingReflag>
    {/* children here are shown when loading finishes */}
  </LoadingReflag>
</ReflagProvider>
```

### Legacy individual props (deprecated)

For backward compatibility, you can still use individual props, but these are deprecated and will be removed in the next major version:

```tsx
<ReflagProvider
  publishableKey={YOUR_PUBLISHABLE_KEY}
  user={{ id: "user_123", name: "John Doe", email: "john@acme.com" }}
  company={{ id: "company_123", name: "Acme, Inc" }}
  otherContext={{ source: "web" }}
>
  <LoadingReflag>
    {/* children here are shown when loading finishes */}
  </LoadingReflag>
</ReflagProvider>
```

> [!Important]
> The `user`, `company`, and `otherContext` props are deprecated. Use the `context` prop instead, which provides the same functionality in a more structured way.

### Context requirements

If you supply `user` or `company` objects, they must include at least the `id` property otherwise they will be ignored in their entirety.
In addition to the `id`, you must also supply anything additional that you want to be able to evaluate flag targeting rules against.
Attributes which are not properties of the `user` or `company` can be supplied using the `other` property.

Attributes cannot be nested (multiple levels) and must be either strings, numbers or booleans.
A number of special attributes exist:

- `name` -- display name for `user`/`company`,
- `email` -- the email of the user,
- `avatar` -- the URL for `user`/`company` avatar image.

To retrieve flags along with their targeting information, use `useFlag(key: string)` hook (described in a section below).

Note that accessing `isEnabled` on the object returned by `useFlag()` automatically
generates a `check` event.

## React Native

For React Native, use `@reflag/react-native-sdk`, which is a thin wrapper around
`@reflag/react-sdk` and wires up AsyncStorage by default.

An Expo example app lives at `packages/react-native-sdk/dev/expo`.

## Remote config

Remote config is a dynamic and flexible approach to configuring flag behavior outside of your app – without needing to re-deploy it.

Similar to `isEnabled`, each flag accessed using the `useFlag()` hook, has a `config` property. This configuration is managed from within Reflag. It is managed similar to the way access to flags is managed, but instead of the
binary `isEnabled` you can have multiple configuration values which are given to different user/companies.

### Get started with Remote config

1. Update your flag definitions:

```typescript
import "@reflag/react-sdk";

// Define your flags by extending the `Flags` interface in @reflag/react-sdk
declare module "@reflag/react-sdk" {
  interface Flags {
    huddle: {
      // change from `boolean` to an object which sets
      // a type for the remote config for `questionnaire`
      maxTokens: number;
      model: string;
    };
  }
}
```

```ts
const {
  isEnabled,
  config: { key, payload },
} = useFlag("huddles");

// isEnabled: true,
// key: "gpt-3.5",
// payload: { maxTokens: 10000, model: "gpt-3.5-beta1" }
```

`key` is mandatory for a config, but if a flag has no config or no config value was matched against the context, the `key` will be `undefined`. Make sure to check against this case when trying to use the configuration in your application. `payload` is an optional JSON value for arbitrary configuration needs.

Note that, similar to `isEnabled`, accessing `config` on the object returned by `useFlag()` automatically
generates a `check` event.

## Toolbar

The Reflag Toolbar is great for toggling flags on/off for yourself to ensure that everything works both when a flag is on and when it's off.

<img width="310" height="265" alt="Toolbar" src="https://github.com/user-attachments/assets/61492915-0d30-446d-a163-3eb16d9024b2" />

The toolbar will automatically appear on `localhost`. However, it can also be incredibly useful in production. You have full control over when it appears through the `toolbar` configuration option passed to the ReflagProvider.

You can pass a simple boolean to force the toolbar to appear/disappear:

```ts
<ReflagProvider
  ...
  // show the toolbar even in production if the user is an internal/admin user
  toolbar={user?.isInternal}
  ...
});
```

## Server-side rendering and bootstrapping

For server-side rendered applications, you can render immediately with pre-fetched flag data using the `ReflagBootstrappedProvider`.

Bootstrapping is also the recommended setup if you want the most resilient feature flag architecture in React. The client renders immediately from flags provided by your server instead of making its initial render depend on a request to Reflag.

If you want "bullet proof feature flags" in a React application, use React bootstrapping together with `flagsFallbackProvider` in the Node SDK. The fallback provider helps your server start with the latest saved snapshot if it cannot reach Reflag during initialization, and bootstrapping gives the React client server-provided flags for its first render.

### Using `ReflagBootstrappedProvider`

The `<ReflagBootstrappedProvider>` component is a specialized version of `ReflagProvider` designed for server-side rendering, preloaded flag scenarios, and high-reliability setups. It uses pre-fetched evaluated state for the initial render, resulting in faster initial page loads, better SSR compatibility, and a more resilient startup path for React applications.

```tsx
import { useState, useEffect } from "react";
import { BootstrappedFlags } from "@reflag/react-sdk";

interface BootstrapData {
  user: User;
  flags: BootstrappedFlags;
}

function useBootstrap() {
  const [data, setData] = useState<BootstrapData | null>(null);

  useEffect(() => {
    fetch("/bootstrap")
      .then((res) => res.json())
      .then(setData);
  }, []);

  return data;
}

// Usage in your app
function App() {
  const { user, flags } = useBootstrap();

  return (
    <AuthProvider user={user}>
      <ReflagBootstrappedProvider
        publishableKey="your-publishable-key"
        flags={flags}
      >
        <Router />
      </ReflagBootstrappedProvider>
    </AuthProvider>
  );
}
```

### Server-side endpoint setup

Create an endpoint that provides bootstrap data to your client application:

```typescript
// server.js or your Express app
import { ReflagClient as ReflagNodeClient } from "@reflag/node-sdk";

const reflagClient = new ReflagNodeClient({
  secretKey: process.env.REFLAG_SECRET_KEY,
});
await reflagClient.initialize();

app.get("/bootstrap", (req, res) => {
  const user = getUser(req); // Get user from your auth system
  const company = getCompany(req); // Get company from your auth system

  const flags = reflagClient.getFlagsForBootstrap({
    user: { id: "user123", name: "John Doe", email: "john@acme.com" },
    company: { id: "company456", name: "Acme Inc", plan: "enterprise" },
    other: { source: "web" },
  });

  res.status(200).json({
    user,
    flags,
  });
});
```

The `flags` object returned by `getFlagsForBootstrap()` contains the full bootstrapped state package:

- `context`: the evaluation context used on the server
- `flags`: the evaluated raw flags
- `flagStateVersion`: an optional version used to avoid redundant live-update refreshes immediately after bootstrapping

If you want live flag updates to continue working after bootstrapping, use a recent `@reflag/node-sdk` so `getFlagsForBootstrap()` includes `flagStateVersion`.

### Next.js Page Router SSR example

For Next.js applications using server-side rendering, you can pre-fetch flags in `getServerSideProps`:

```typescript
// pages/index.tsx
import { GetServerSideProps } from "next";
import { ReflagClient as ReflagNodeClient } from "@reflag/node-sdk";
import { ReflagBootstrappedProvider, BootstrappedFlags, useFlag } from "@reflag/react-sdk";

interface PageProps {
  bootstrapData: BootstrappedFlags;
}

export const getServerSideProps: GetServerSideProps = async (context) => {
  const serverClient = new ReflagNodeClient({
    secretKey: process.env.REFLAG_SECRET_KEY
  });
  await serverClient.initialize();

  const user = await getUserFromSession(context.req);
  const company = await getCompanyFromUser(user);

  const bootstrapData = serverClient.getFlagsForBootstrap({
    user: { id: "user123", name: "John Doe", email: "john@acme.com" },
    company: { id: "company456", name: "Acme Inc", plan: "enterprise" },
    other: { page: "homepage" }
  });

  return { props: { bootstrapData } };
};

export default function HomePage({ bootstrapData }: PageProps) {
  return (
    <ReflagBootstrappedProvider
      publishableKey={process.env.NEXT_PUBLIC_REFLAG_PUBLISHABLE_KEY}
      flags={bootstrapData}
    >
      <HuddleFeature />
    </ReflagBootstrappedProvider>
  );
}

function HuddleFeature() {
  const { isEnabled, track, config } = useFlag("huddle");

  if (!isEnabled) return null;

  return (
    <div>
      <h2>Start a Huddle</h2>
      <p>Max participants: {config.payload?.maxParticipants ?? 10}</p>
      <p>Video quality: {config.payload?.videoQuality ?? "standard"}</p>
      <button onClick={track}>Start Huddle</button>
    </div>
  );
}
```

This approach eliminates loading states and removes the initial render's dependency on the flags API.

### Next.js App Router example

For Next.js applications using the App Router (Next.js 13+), you can pre-fetch flags in Server Components and pass them to client components:

```typescript
// app/layout.tsx (Server Component)
import { ReflagClient as ReflagNodeClient } from "@reflag/node-sdk";
import { ClientProviders } from "./providers";

async function getBootstrapData() {
  const serverClient = new ReflagNodeClient({
    secretKey: process.env.REFLAG_SECRET_KEY!
  });
  await serverClient.initialize();

  // In a real app, you'd get user/company from your auth system
  const bootstrapData = serverClient.getFlagsForBootstrap({
    user: { id: "user123", name: "John Doe", email: "john@acme.com" },
    company: { id: "company456", name: "Acme Inc", plan: "enterprise" },
    other: { source: "web" }
  });

  return bootstrapData;
}

export default async function RootLayout({
  children,
}: {
  children: React.ReactNode;
}) {
  const bootstrapData = await getBootstrapData();

  return (
    <html lang="en">
      <body>
        <ClientProviders bootstrapData={bootstrapData}>
          {children}
        </ClientProviders>
      </body>
    </html>
  );
}
```

```typescript
// app/providers.tsx (Client Component)
"use client";

import { ReflagBootstrappedProvider, BootstrappedFlags } from "@reflag/react-sdk";

interface ClientProvidersProps {
  children: React.ReactNode;
  bootstrapData: BootstrappedFlags;
}

export function ClientProviders({ children, bootstrapData }: ClientProvidersProps) {
  return (
    <ReflagBootstrappedProvider
      publishableKey={process.env.NEXT_PUBLIC_REFLAG_PUBLISHABLE_KEY!}
      flags={bootstrapData}
    >
      {children}
    </ReflagBootstrappedProvider>
  );
}
```

```typescript
// app/page.tsx (Server Component)
import { HuddleFeature } from "./huddle-feature";

export default function HomePage() {
  return (
    <main>
      <h1>My App</h1>
      <HuddleFeature />
    </main>
  );
}
```

```typescript
// app/huddle-feature.tsx (Client Component)
"use client";

import { useFlag } from "@reflag/react-sdk";

export function HuddleFeature() {
  const { isEnabled, track, config } = useFlag("huddle");

  if (!isEnabled) return null;

  return (
    <div>
      <h2>Start a Huddle</h2>
      <p>Max participants: {config.payload?.maxParticipants ?? 10}</p>
      <p>Video quality: {config.payload?.videoQuality ?? "standard"}</p>
      <button onClick={track}>Start Huddle</button>
    </div>
  );
}
```

This App Router approach leverages Server Components for server-side flag fetching while using Client Components only where React state and hooks are needed.

## `<ReflagClientProvider>` component

The `<ReflagClientProvider>` is a lower-level component that accepts a `ReflagClient` instance. This is useful for advanced use cases where you need full control over client initialization or want to share a client instance across multiple parts of your application.

In most cases you should initialize the client before rendering this provider. If you pass an idle client and enable `suspense`, a `useFlag()` call that suspends can initialize the client on demand; without Suspense, you must initialize the client yourself.

### Usage

```tsx
import { ReflagClient } from "@reflag/browser-sdk";
import { ReflagClientProvider } from "@reflag/react-sdk";

// Initialize the client yourself
const client = new ReflagClient({
  publishableKey: "your-publishable-key",
  user: { id: "user123", name: "John Doe" },
  company: { id: "company456", name: "Acme Inc" },
  // ... other configuration options
});

// Initialize the client
await client.initialize();

function App() {
  return (
    <ReflagClientProvider client={client} loadingComponent={<Loading />}>
      <Router />
    </ReflagClientProvider>
  );
}
```

### Props

The `ReflagClientProvider` accepts the following props:

- `client`: A `ReflagClient` instance. Prefer passing an already-initialized client; idle clients are initialized on demand only by suspense-enabled `useFlag()` calls.
- `loadingComponent`: Optional React component to show while the client is initializing (same as `ReflagProvider`)
- `suspense`: Optional. Set to `true` to make `useFlag()` suspend while the client is loading

> [!Note]
> Most applications should use `ReflagProvider` or `ReflagBootstrappedProvider` instead of `ReflagClientProvider`. Only use this component when you need the advanced control it provides.

## `<ReflagProvider>` component

The `<ReflagProvider>` initializes the Reflag SDK, fetches flags and starts listening for automated feedback survey events. The component can be configured using a number of props:

- `publishableKey` is used to connect the provider to an _environment_ on Reflag. Find your `publishableKey` under [environment settings](https://app.reflag.com/env-current/settings/app-environments) in Reflag,
- `context` (recommended): An object containing `user`, `company`, and `other` properties that make up the evaluation context used to determine if a flag is enabled or not. `company` and `user` contexts are automatically transmitted to Reflag servers so the Reflag app can show you which companies have access to which flags etc.
- `company`, `user` and `other` (deprecated): Individual props for context. These are deprecated in favor of the `context` prop and will be removed in the next major version.
  > [!Note]
  > If you specify `company` and/or `user` they must have at least the `id` property, otherwise they will be ignored in their entirety. You should also supply anything additional you want to be able to evaluate flag targeting against,
- `fallbackFlags`: A list of strings which specify which flags to consider enabled if the SDK is unable to fetch flags. Can be provided in two formats:

  ```ts
  // Simple array of flag keys
  fallbackFlags={["flag1", "flag2"]}

  // Or with configuration overrides
  fallbackFlags: {
      "flag1": true,  // just enable the flag
      "flag2": {      // enable with configuration
        key: "variant-a",
        payload: {
          limit: 100,
          mode: "test"
        }
      }
  }
  ```

- `timeoutMs`: Timeout in milliseconds when fetching flags from the server.
- `staleWhileRevalidate`: If set to `true`, stale flags will be returned while refetching flags in the background.
- `expireTimeMs`: If set, flags will be cached between page loads for this duration (in milliseconds).
- `staleTimeMs`: Maximum time (in milliseconds) that stale flags will be returned if `staleWhileRevalidate` is true and new flags cannot be fetched.
- `offline`: Provide this option when testing or in local development environments to avoid contacting Reflag servers.
- `loadingComponent` lets you specify an React component to be rendered instead of the children while the Reflag provider is initializing. If you want more control over loading screens, `useFlag()` and `useIsLoading` returns `isLoading` which you can use to customize the loading experience.
- `suspense`: Set to `true` to make `useFlag()` suspend while the provider is loading and `useOptInFlags()` suspend while required opt-in metadata is loading. Wrap components that call these hooks in React `<Suspense>` boundaries and omit `loadingComponent` if you want Suspense fallbacks to control loading UI.
- `enableTracking`: Set to `false` to stop sending tracking events and user/company updates to Reflag. Useful when you're impersonating a user (defaults to `true`),
- `enableLiveFlagUpdates`: Enables live flag updates over SSE. Defaults to `true` in the React SDK.
- `apiBaseUrl`: Optional base URL for the Reflag API. This also controls the SSE origin used for live flag updates and automated feedback,
- `credentials`: Optional fetch credentials mode. Set to `"include"` when proxying through your backend and authenticating with cookies; this also enables credentials for live-update SSE connections.
- `appBaseUrl`: Optional base URL for the Reflag application. Use this to override the default app URL,

- `logger`: Optional custom logger implementation (`debug`, `info`, `warn`, `error`) used by the underlying client,
- `debug`: Set to `true` to enable debug logging to the console. If both `logger` and `debug` are provided, `logger` takes precedence,
- `toolbar`: Optional [configuration](https://docs.reflag.com/supported-languages/browser-sdk/globals#toolbaroptions) for the Reflag toolbar,
- `feedback`: Optional configuration for feedback collection

## `<ReflagBootstrappedProvider>` component

The `<ReflagBootstrappedProvider>` is a specialized version of the `ReflagProvider` that uses pre-fetched flag data for the initial render. This is ideal for server-side rendering scenarios.

The component accepts the following props:

- `flags`: Pre-fetched bootstrapped state of type `BootstrappedFlags` obtained from the Node SDK's `getFlagsForBootstrap()` method. This contains the context (`flags.context`), the evaluated flags (`flags.flags`), and an optional `flags.flagStateVersion`.
- All other props available in [`ReflagProvider`](#reflagprovider-component) are supported except `context`, `user`, `company`, and `other` (which are extracted from `flags.context`).

**Example:**

```tsx
import {
  ReflagBootstrappedProvider,
  BootstrappedFlags,
} from "@reflag/react-sdk";

interface AppProps {
  bootstrapData: BootstrappedFlags;
}

function App({ bootstrapData }: AppProps) {
  return (
    <ReflagBootstrappedProvider
      publishableKey="your-publishable-key"
      flags={bootstrapData}
      loadingComponent={<Loading />}
      debug={process.env.NODE_ENV === "development"}
    >
      <Router />
    </ReflagBootstrappedProvider>
  );
}
```

> [!Note]
> When using `ReflagBootstrappedProvider`, pass the entire object returned by `getFlagsForBootstrap()` directly as the `flags` prop. The context is extracted from `flags.context`, and `flags.flagStateVersion` is used when present.
>
> With `ReflagBootstrappedProvider`, `useOptInFlags()` requests a flags refresh on first use. It returns `isLoading: true` (or suspends) until that refresh settles.
>
> If you want live flag updates to continue working after bootstrapping, use a recent `@reflag/node-sdk` so `getFlagsForBootstrap()` includes `flagStateVersion`.
>
> After bootstrapping, any live flag updates are fetched directly by the browser SDK from Reflag using the browser-visible context. If your bootstrapped snapshot depends on server-only or secret context that is not available in the browser, later live refreshes may differ. In that case, keep `enableLiveFlagUpdates` disabled.
>
> Requesting opt-in flags also triggers a browser-side refresh, even when `enableLiveFlagUpdates` is disabled.

## Hooks

### `useFlag()`

Returns the state of a given flag for the current context. The hook provides type-safe access to flags and their configurations.

```tsx
import { useFlag } from "@reflag/react-sdk";
import { Loading } from "./Loading";

function StartHuddleButton() {
  const {
    isLoading, // true while flags are being loaded
    isEnabled, // boolean indicating if the flag is enabled
    config: {
      // flag configuration
      key, // string identifier for the config variant
      payload, // type-safe configuration object
    },
    track, // function to track flag usage
    requestFeedback, // function to request feedback for this flag
  } = useFlag("huddle");

  if (isLoading) {
    return <Loading />;
  }

  if (!isEnabled) {
    return null;
  }

  return (
    <>
      <button onClick={track}>Start huddle!</button>
      <button
        onClick={(e) =>
          requestFeedback({
            title: payload?.question ?? "How do you like the Huddles feature?",
            position: {
              type: "POPOVER",
              anchor: e.currentTarget as HTMLElement,
            },
          })
        }
      >
        Give feedback!
      </button>
    </>
  );
}
```

#### Suspense loading

Enable `suspense` on the provider to have `useFlag()` throw a promise while `isLoading` is true. The nearest `<Suspense>` boundary will render its fallback until flags are ready.

```tsx
import { Suspense } from "react";
import { ReflagProvider } from "@reflag/react-sdk";

<ReflagProvider publishableKey="..." context={context} suspense>
  <Suspense fallback={<Loading />}>
    <AppRoutes />
  </Suspense>
</ReflagProvider>;
```

You can also opt in for a single call with `useFlag("huddle", { suspense: true })`, or opt out inside a suspense-enabled provider with `{ suspense: false }`.

### `useOptInFlags()` and `useSetOptIn()`

Use these hooks to build an end-user opt-in UI for flags where opt-in is enabled in Reflag.

```tsx
import {
  type OptInFlag,
  useIsLoading,
  useOptInFlags,
  useSetOptIn,
} from "@reflag/react-sdk";

function OptInList() {
  const isProviderLoading = useIsLoading();
  const { flags, isLoading } = useOptInFlags();
  const setOptIn = useSetOptIn();

  async function toggleOptIn(flag: OptInFlag) {
    try {
      const response = await setOptIn(flag.key, {
        optedIn: !flag.userOptedIn,
      });
      if (!response?.ok) {
        console.error("Could not update opt-in");
      }
    } catch (error) {
      console.error("Could not update opt-in", error);
    }
  }

  if (isProviderLoading || isLoading) {
    return <p>Loading…</p>;
  }

  return flags.map((flag) => (
    <button type="button" key={flag.key} onClick={() => toggleOptIn(flag)}>
      {flag.userOptedIn ? "Cancel opt-in" : `Try ${flag.name}`}
    </button>
  ));
}
```

By default, `useSetOptIn()` changes the opt-in for the current user, so the current context must include a `user.id`. To manage the current company's opt-in instead, pass `scope: "company"`; the context must then include a `company.id`.

User and company opt-ins are managed independently. Setting `optedIn` to `false` removes the opt-in only for the selected scope. For example, cancelling a user's opt-in does not change the company's opt-in for the same flag.

`setOptIn` returns a promise so you can wait for the new membership state to be synchronized. On success, it resolves after the refreshed flag state has been applied locally, the requested membership change has been confirmed, and subscribers have been notified when flags change. React may not have committed the resulting render yet.

The promise resolves to a `Response`, or `undefined` if skipped due to invalid input, offline mode etc. Check `response?.ok` for success.

`useOptInFlags()` returns `{ flags, isLoading }`. With `ReflagBootstrappedProvider`, it fetches opt-in metadata on first use and reports `isLoading: true` until that refresh succeeds or fails.

If fetching opt-in metadata fails, loading ends without exposing an error. Call `client.refresh()` on the client returned by `useClient()` to retry.

With a regular `ReflagProvider`, opt-in metadata arrives as part of the normal initial flags request, so `useOptInFlags().isLoading` remains `false`. Use the general `useIsLoading()` hook or the provider's `loadingComponent` for that initial loading state.

`useOptInFlags()` also supports Suspense. It respects the provider-level `suspense` option, or you can enable it for only this hook with `useOptInFlags({ suspense: true })`. While required opt-in metadata is loading, the nearest `<Suspense>` boundary renders its fallback:

```tsx
import { Suspense } from "react";

<ReflagBootstrappedProvider publishableKey="..." flags={bootstrapData} suspense>
  <Suspense fallback={<Spinner />}>
    <OptInList />
  </Suspense>
</ReflagBootstrappedProvider>;
```

Opt-in metadata Suspense is primarily relevant with `ReflagBootstrappedProvider`. Use `useOptInFlags({ suspense: false })` to opt out for one call when Suspense is enabled on the provider.

### `useTrack()`

`useTrack()` lets you send custom events to Reflag. Use this whenever a user _uses_ a feature. These events can be used to analyze feature usage in Reflag.

```tsx
import { useTrack } from "@reflag/react-sdk";

function StartHuddle() {
  const { track } = useTrack();
  <div>
    <button onClick={() => track("Huddle Started", { huddleType: "voice" })}>
      Start voice huddle!
    </button>
  </div>;
}
```

### `useRequestFeedback()`

`useRequestFeedback()` returns a function that lets you open up a dialog to ask for feedback on a specific feature. This is useful for collecting targeted feedback about specific features as part of roll out. See [Automated Feedback Surveys](https://docs.reflag.com/product-handbook/live-satisfaction) for how to do this automatically, without code.

When using the `useRequestFeedback` you must pass the flag key to `requestFeedback`.
The example below shows how to use `position` to ensure the popover appears next to the "Give feedback!" button.

```tsx
import { useRequestFeedback } from "@reflag/react-sdk";

function FeedbackButton() {
  const requestFeedback = useRequestFeedback();
  return (
    <button
      onClick={(e) =>
        requestFeedback({
          flagKey: "huddle-flag",
          title: "How satisfied are you with file uploads?",
          position: {
            type: "POPOVER",
            anchor: e.currentTarget as HTMLElement,
          },
          // Optional custom styling
          style: {
            theme: "light",
            primaryColor: "#007AFF",
          },
        })
      }
    >
      Give feedback!
    </button>
  );
}
```

See the [Feedback Documentation](https://github.com/reflagcom/javascript/blob/main/packages/browser-sdk/FEEDBACK.md#manual-feedback-collection) for more information on `requestFeedback` options.

### `useSendFeedback()`

Returns a function that lets you send feedback to Reflag. This is useful if you've manually collected feedback through your own UI and want to send it to Reflag.

```tsx
import { useSendFeedback } from "@reflag/react-sdk";

function CustomFeedbackForm() {
  const sendFeedback = useSendFeedback();

  const handleSubmit = async (data: FormData) => {
    await sendFeedback({
      flagKey: "reflag-flag-key",
      score: parseInt(data.get("score") as string),
      comment: data.get("comment") as string,
    });
  };

  return <form onSubmit={handleSubmit}>...</form>;
}
```

### `useUpdateUser()`, `useUpdateCompany()` and `useUpdateOtherContext()`

These hooks return functions that let you update the attributes for the currently set user, company, or other context. Updates to user/company are stored remotely and affect flag targeting, while "other" context updates only affect the current session.

```tsx
import {
  useUpdateUser,
  useUpdateCompany,
  useUpdateOtherContext,
} from "@reflag/react-sdk";

function FlagOptIn() {
  const updateUser = useUpdateUser();
  const updateCompany = useUpdateCompany();
  const updateOtherContext = useUpdateOtherContext();

  const handleUserUpdate = async () => {
    await updateUser({
      role: "admin",
      betaFlags: "enabled",
    });
  };

  const handleCompanyUpdate = async () => {
    await updateCompany({
      plan: "enterprise",
      employees: 500,
    });
  };

  const handleContextUpdate = async () => {
    await updateOtherContext({
      currentWorkspace: "workspace-123",
      theme: "dark",
    });
  };

  return (
    <div>
      <button onClick={handleUserUpdate}>Update User</button>
      <button onClick={handleCompanyUpdate}>Update Company</button>
      <button onClick={handleContextUpdate}>Update Context</button>
    </div>
  );
}
```

### `useClient()`

Returns the `ReflagClient` used by the `ReflagProvider`. The client offers more functionality that
is not directly accessible thorough the other hooks.

```tsx
import { useClient } from "@reflag/react-sdk";

function LoggingWrapper({ children }: { children: ReactNode }) {
  const client = useClient();

  console.log(client.getContext());

  return children;
}
```

### `useIsLoading()`

Returns the loading state of the flags in the `ReflagClient`.
Initially, the value will be `true` if no bootstrap flags have been provided and the client has not be initialized.

```tsx
import { useIsLoading } from "@reflag/react-sdk";
import { Spinner } from "./Spinner";

function LoadingWrapper({ children }: { children: ReactNode }) {
  const isLoading = useIsLoading();

  if (isLoading) {
    return <Spinner />;
  }

  return children;
}
```

### `useOnEvent()`

Attach a callback handler to client events to act on changes. It automatically disposes itself on unmount.

```tsx
import { useOnEvent } from "@reflag/react-sdk";

function LoggingWrapper({ children }: { children: ReactNode }) {
  useOnEvent("flagsUpdated", (newFlags) => {
    console.log(newFlags);
  });

  return children;
}
```

## Migrating from Bucket SDK

If you have been using the Bucket SDKs, the following list will help you migrate to Reflag SDK:

- `Bucket*` classes, and types have been renamed to `Reflag*` (e.g. `BucketClient` is now `ReflagClient`)
- `Feature*` classes, and types have been renamed to `Flag*` (e.g. `Feature` is now `Flag`, `RawFeatures` is now `RawFlags`)
- When using strongly-typed flags, the new `Flags` interface replaced `Features` interface
- All methods that contained `feature` in the name have been renamed to use the `flag` terminology (e.g. `getFeature` is `getFlag`)
- The `fallbackFeatures` property in client constructor and configuration files has been renamed to `fallbackFlags`
- `featureKey` has been renamed to `flagKey` in all methods that accepts that argument
- The SDKs will not emit `evaluate` and `evaluate-config` events anymore
- The new cookies that are stored in the client's browser are now `reflag-*` prefixed instead of `bucket-*`
- The `featuresUpdated` hook has been renamed to `flagsUpdated`
- The `checkIsEnabled` and `checkConfig` hooks have been removed, use `check` from now on

To ease in transition to Reflag SDK, some of the old methods have been preserved as aliases to the new methods:

- `getFeature` method is an alias for `getFlag`
- `getFeatures` method is an alias for `getFlags`
- `useFeature` method is an alias for `useFlag`
- `featuresUpdated` hook is an alias for `flagsUpdated`

If you are running with strict Content Security Policies active on your website, you will need change them as follows:

- `connect-src https://front.bucket.co` to `connect-src https://front.reflag.com`

## Content Security Policy (CSP)

See [CSP](https://github.com/reflagcom/javascript/blob/main/packages/browser-sdk/README.md#content-security-policy-csp) for info on using Reflag React SDK with CSP

## License

MIT License

Copyright (c) 2025 Bucket ApS