> ## Documentation Index
> Fetch the complete documentation index at: https://cometchat-22654f5b-docs-rn-guide-message-privately.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Chat SDK

> Add CometChat Chat SDK to Flutter apps with real-time messaging, users, groups, conversations, and cross-platform support.

The CometChat Chat SDK for Flutter enables real-time messaging, user management, group conversations, and more in your Flutter application. Built as a pure Dart implementation in v5, it removes the dependency on platform channels and works seamlessly across Android, iOS, Web, and desktop.

<Info>
  **Faster Integration with UI Kits**

  If you're using CometChat UI Kits, messaging features can be quickly integrated with pre-built components:

  * Conversation lists, message composers, and thread views
  * Typing indicators, read receipts, and reactions
  * Group management and user profiles

  👉 [Flutter UI Kit Overview](/ui-kit/flutter/overview)

  Use this Chat SDK directly only if you need custom UI or advanced control.
</Info>

<Warning>
  **Upgrading from v4?**

  If you're migrating an existing app from CometChat SDK v4, check out the [Upgrading from v4](/sdk/flutter/upgrading-from-v4-guide) guide for breaking changes, deprecated methods, and migration instructions.
</Warning>

Before integrating the Chat SDK, ensure you have a [CometChat Account](https://app.cometchat.com/signup) with your App ID, Region, and Auth Key. Flutter SDK `>=1.2` is required, with Android API Level 21+ and iOS 11+. Users must exist in CometChat to send or receive messages — see [Authentication](/sdk/flutter/authentication-overview) for details.

```mermaid theme={null}
sequenceDiagram
    participant App
    participant CometChat

    App->>CometChat: init(appId, appSettings)
    App->>CometChat: login(uid, authKey)
    CometChat-->>App: User
    App->>CometChat: sendMessage() / addMessageListener()
    CometChat-->>App: Real-time events (messages, typing, presence)
    App->>CometChat: logout()
```

<CardGroup cols={2}>
  <Card title="Messaging" icon="message" href="/sdk/flutter/messaging-overview">
    Send text, media, and custom messages in 1-on-1 or group conversations
  </Card>

  <Card title="Groups" icon="users" href="/sdk/flutter/groups-overview">
    Create, join, and manage group conversations with member roles and scopes
  </Card>

  <Card title="Real-time Listeners" icon="bolt" href="/sdk/flutter/real-time-listeners">
    Listen for messages, typing indicators, read receipts, and presence changes in real time
  </Card>

  <Card title="Typing Indicators" icon="keyboard" href="/sdk/flutter/typing-indicators">
    Show real-time typing status for users and groups
  </Card>

  <Card title="User Presence" icon="circle-dot" href="/sdk/flutter/user-presence">
    Track online/offline status of users with configurable subscription modes
  </Card>

  <Card title="Reactions" icon="face-smile" href="/sdk/flutter/reactions">
    Add and manage emoji reactions on messages
  </Card>

  <Card title="Threaded Messages" icon="comments" href="/sdk/flutter/threaded-messages">
    Organize conversations with message threads
  </Card>

  <Card title="Delivery & Read Receipts" icon="check-double" href="/sdk/flutter/delivery-read-receipts">
    Track message delivery and read status
  </Card>

  <Card title="AI Agents" icon="robot" href="/sdk/flutter/ai-agents">
    Integrate AI-powered agents into your chat experience
  </Card>

  <Card title="Calling" icon="phone" href="/sdk/flutter/calling-overview">
    Voice and video calling with built-in UI components
  </Card>
</CardGroup>

| Component            | Description                                                                          |
| -------------------- | ------------------------------------------------------------------------------------ |
| `CometChat`          | Main entry point for initialization, authentication, messaging, and real-time events |
| `AppSettings`        | Configuration for SDK initialization (App ID, Region, presence subscription)         |
| `User`               | Represents a CometChat user with UID, name, avatar, and metadata                     |
| `Group`              | Represents a group conversation with GUID, type, and member management               |
| `BaseMessage`        | Base class for all message types (text, media, custom, action)                       |
| `MessageListener`    | Event interface for real-time message, typing, and receipt events                    |
| `ConnectionListener` | Event interface for WebSocket connection status changes                              |