> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/bitwarden/clients/llms.txt
> Use this file to discover all available pages before exploring further.

# State Management Library

> State management libraries for Bitwarden clients

## State Management Libraries

Bitwarden uses several libraries for centralized state management across all client applications.

## Core Libraries

<CardGroup cols={2}>
  <Card title="@bitwarden/state" icon="database" href="/guide/state/overview">
    State Provider Framework for centralized state management
  </Card>

  <Card title="@bitwarden/state-internal" icon="lock">
    Internal state management utilities and implementations
  </Card>
</CardGroup>

## State Provider Framework

The `@bitwarden/state` library provides the State Provider Framework, which enables:

* **Domain ownership** - Teams own their state definitions
* **Best practices enforcement** - Reduces boilerplate and prevents mistakes
* **Multi-account support** - Built-in account switching
* **Reactive observables** - Trustworthy state streams
* **Testing support** - Comprehensive fake/mock implementations

### Key Components

* **StateProvider** - Main entry point for accessing state
* **StateDefinition** - Defines storage location and namespace
* **KeyDefinition** - Defines specific state keys with serialization
* **GlobalState** - Application-wide state
* **SingleUserState** - User-scoped state
* **DerivedState** - Computed state based on other state

## State Testing Utilities

The `@bitwarden/state-test-utils` library provides testing utilities:

```typescript theme={null}
import { FakeStateProvider } from "@bitwarden/state-test-utils";

describe("MyService", () => {
  let stateProvider: FakeStateProvider;

  beforeEach(() => {
    stateProvider = new FakeStateProvider();
  });

  it("should update state", async () => {
    const service = new MyService(stateProvider);
    await service.setSetting("value");
    
    const state = stateProvider.getGlobal(MY_SETTING);
    expect(await firstValueFrom(state.state$)).toBe("value");
  });
});
```

## Storage Locations

State can be persisted in different locations depending on requirements:

* **Disk** - Persistent storage (survives app restarts)
* **Memory** - In-memory cache (cleared on restart)
* **Disk-Local** (Web only) - Local storage instead of session storage

Platform-specific implementations handle the actual storage mechanism:

* **Browser**: chrome.storage API or browser.storage API
* **Desktop**: Electron's native storage
* **Web**: localStorage or sessionStorage
* **CLI**: File-based storage

## Learn More

<CardGroup cols={2}>
  <Card title="State Overview" icon="book" href="/guide/state/overview">
    Learn about the State Provider Framework
  </Card>

  <Card title="State Services" icon="server" href="/guide/state/services">
    How to use state in services
  </Card>

  <Card title="State Migrations" icon="arrow-right-arrow-left" href="/guide/state/migrations">
    Migrating state between versions
  </Card>

  <Card title="Platform Library" icon="layer-group" href="/libs/platform">
    Platform abstractions and services
  </Card>
</CardGroup>