Real-Time Events

Listen for incoming messages, presence changes, typing indicators, receipts, group events, and connection state.

The UCometChatSubsystem exposes 40+ multicast delegates organized by listener type. All delegates fire on the Game Thread, so you can safely update UI directly.

Event Flow

Bind delegates before calling Login. Events that arrive between Login completing and your bindings being set up will be missed.

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Binding Delegates

Blueprint

1. Get a reference to the CometChat Subsystem
2. Drag off the Subsystem pin and search for the delegate name (e.g., On Text Message Received)
3. Select Bind Event to wire it to a custom event node
4. The custom event automatically gets the correct parameter type

C++

void AMyActor::BeginPlay()
{
    Super::BeginPlay();

    UCometChatSubsystem* Chat = GetGameInstance()->GetSubsystem<UCometChatSubsystem>();

    // Message events
    Chat->OnTextMessageReceived.AddDynamic(this, &AMyActor::HandleTextMessage);
    Chat->OnTypingStarted.AddDynamic(this, &AMyActor::HandleTypingStarted);

    // User events
    Chat->OnUserOnline.AddDynamic(this, &AMyActor::HandleUserOnline);

    // Group events
    Chat->OnGroupMemberJoined.AddDynamic(this, &AMyActor::HandleMemberJoined);

    // Connection events
    Chat->OnConnected.AddDynamic(this, &AMyActor::HandleConnected);
    Chat->OnDisconnected.AddDynamic(this, &AMyActor::HandleDisconnected);
}

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MessageListener Events

These fire when messages, typing indicators, receipts, or reactions arrive.

Delegate	Payload	Fires When
OnTextMessageReceived	FCometChatMessage	A text message arrives
OnMediaMessageReceived	FCometChatMessage	A media (image/video/audio/file) message arrives
OnCustomMessageReceived	FCometChatMessage	A custom message arrives
OnInteractiveMessageReceived	FCometChatMessage	An interactive message arrives
OnInteractionGoalCompleted	FCometChatInteractionReceipt	An interaction goal is completed
OnTypingStarted	FCometChatTypingIndicator	A user starts typing
OnTypingEnded	FCometChatTypingIndicator	A user stops typing
OnMessagesDelivered	FCometChatMessageReceipt	Messages delivered to recipient
OnMessagesRead	FCometChatMessageReceipt	Messages read by recipient
OnMessagesDeliveredToAll	FCometChatMessageReceipt	Messages delivered to all group members
OnMessagesReadByAll	FCometChatMessageReceipt	Messages read by all group members
OnMessageEdited	FCometChatMessage	A message is edited
OnMessageDeleted	FCometChatMessage	A message is deleted
OnTransientMessageReceived	FCometChatTransientMessage	A transient (ephemeral) message arrives
OnMessageReactionAdded	FCometChatReactionEvent	A reaction is added to a message
OnMessageReactionRemoved	FCometChatReactionEvent	A reaction is removed from a message
OnMessageModerated	FCometChatMessage	A message moderation status changes
OnAIAssistantMessageReceived	FCometChatMessage	An AI assistant message arrives
OnAIToolResultReceived	FCometChatMessage	An AI tool result arrives
OnAIToolArgumentsReceived	FCometChatMessage	AI tool arguments arrive

Blueprint

Bind to On Text Message Received. The custom event receives an FCometChatMessage. Use ReceiverType to check if it’s a user (1:1) or group message.

C++

void AMyActor::HandleTextMessage(const FCometChatMessage& Message)
{
    if (Message.ReceiverType == TEXT("group"))
    {
        UE_LOG(LogTemp, Log, TEXT("[Group %s] %s: %s"),
            *Message.ReceiverUid, *Message.SenderName, *Message.Text);
    }
    else
    {
        UE_LOG(LogTemp, Log, TEXT("[DM] %s: %s"),
            *Message.SenderName, *Message.Text);
    }
}

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UserListener Events

These fire when a user’s online status changes.

Delegate	Payload	Fires When
OnUserOnline	FCometChatUser	A user comes online
OnUserOffline	FCometChatUser	A user goes offline

Blueprint

Bind to On User Online / On User Offline. The custom event receives an FCometChatUser with the user’s full profile.

C++

void AMyActor::HandleUserOnline(const FCometChatUser& User)
{
    UE_LOG(LogTemp, Log, TEXT("%s is now online"), *User.Name);
}

void AMyActor::HandleUserOffline(const FCometChatUser& User)
{
    UE_LOG(LogTemp, Log, TEXT("%s went offline"), *User.Name);
}

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GroupListener Events

These fire when group membership changes occur.

Delegate	Payload	Fires When
OnGroupMemberJoined	FCometChatAction, FCometChatUser, FCometChatGroup	A user joins a group
OnGroupMemberLeft	FCometChatAction, FCometChatUser, FCometChatGroup	A user leaves a group
OnGroupMemberKicked	FCometChatAction, FCometChatUser, FCometChatUser, FCometChatGroup	A member is kicked (includes who kicked)
OnGroupMemberBanned	FCometChatAction, FCometChatUser, FCometChatUser, FCometChatGroup	A member is banned (includes who banned)
OnGroupMemberUnbanned	FCometChatAction, FCometChatUser, FCometChatUser, FCometChatGroup	A member is unbanned
OnGroupMemberScopeChanged	FCometChatScopeChangeEvent	A member’s role/scope changes
OnMemberAddedToGroup	FCometChatAction, FCometChatUser, FCometChatUser, FCometChatGroup	A member is added by another user

Blueprint

Bind to On Group Member Joined. The custom event receives the action, the user who joined, and the group.

C++

void AMyActor::HandleMemberJoined(const FCometChatAction& Action,
    const FCometChatUser& JoinedUser, const FCometChatGroup& Group)
{
    UE_LOG(LogTemp, Log, TEXT("%s joined group %s"), *JoinedUser.Name, *Group.Name);
}

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ConnectionListener Events

These fire when the WebSocket connection state changes.

Delegate	Payload	Fires When
OnConnected	—	WebSocket connection established
OnConnecting	—	SDK is attempting to connect
OnDisconnected	—	WebSocket connection lost
OnFeatureThrottled	—	A feature is being rate-limited
OnConnectionError	FCometChatError	A connection error occurred

Blueprint

Bind to On Connected, On Disconnected, etc. These are parameterless events (except OnConnectionError which provides an FCometChatError).

C++

void AMyActor::HandleConnected()
{
    UE_LOG(LogTemp, Log, TEXT("Connected to CometChat"));
}

void AMyActor::HandleDisconnected()
{
    UE_LOG(LogTemp, Warning, TEXT("Disconnected from CometChat"));
}

void AMyActor::HandleConnectionError(const FCometChatError& Error)
{
    UE_LOG(LogTemp, Error, TEXT("Connection error: %s — %s"), *Error.Code, *Error.Message);
}

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LoginListener Events

These fire on login/logout lifecycle events.

Delegate	Payload	Fires When
OnLoginSuccess	FCometChatUser	Login succeeds
OnLoginFailure	FCometChatError	Login fails
OnLogoutSuccess	—	Logout succeeds
OnLogoutFailure	FCometChatError	Logout fails

Blueprint

Bind to On Login Success to receive the logged-in FCometChatUser after authentication completes.

C++

void AMyActor::HandleLoginSuccess(const FCometChatUser& User)
{
    UE_LOG(LogTemp, Log, TEXT("Logged in as %s (%s)"), *User.Name, *User.Uid);
}

void AMyActor::HandleLoginFailure(const FCometChatError& Error)
{
    UE_LOG(LogTemp, Error, TEXT("Login failed: %s"), *Error.Message);
}

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AIAssistantListener Events

These fire when AI assistant interactions occur.

Delegate	Payload	Fires When
OnAIAssistantEvent	FCometChatAIAssistantEvent	An AI assistant event occurs

Blueprint

Bind to On AI Assistant Event. The custom event receives an FCometChatAIAssistantEvent with event type, data, conversation ID, and sender UID.

C++

void AMyActor::HandleAIAssistantEvent(const FCometChatAIAssistantEvent& Event)
{
    UE_LOG(LogTemp, Log, TEXT("AI event [%s] in conversation %s: %s"),
        *Event.EventType, *Event.ConversationId, *Event.Data);
}

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Error Handling — FCometChatError

Many delegates and failure callbacks provide an FCometChatError struct with details about what went wrong. Always handle errors gracefully in your game.

FCometChatError

Property	Type	Description
Code	FString	Machine-readable error code (e.g., "ERR_AUTH_FAILED", "ERR_NETWORK")
Message	FString	Human-readable error description
Details	FString	Additional context (may be empty)

Handling Errors

Blueprint

All async nodes have an On Failure pin. Wire it to a custom event that receives an FString error message. Connection and login listener events provide the full FCometChatError struct.

C++

// Async node failure handler (simple string)
void AMyActor::HandleError(const FString& Error)
{
    UE_LOG(LogTemp, Error, TEXT("Operation failed: %s"), *Error);
    // Show error in UI, retry, or fallback
}

// Connection/Login listener error handler (full struct)
void AMyActor::HandleConnectionError(const FCometChatError& Error)
{
    UE_LOG(LogTemp, Error, TEXT("Error [%s]: %s — %s"),
        *Error.Code, *Error.Message, *Error.Details);

    // Common patterns:
    // - "ERR_NETWORK": Show "No internet" banner, retry with backoff
    // - "ERR_AUTH_FAILED": Redirect to login screen
    // - "ERR_RATE_LIMIT": Wait and retry after delay
}

Best practice: Always bind OnConnectionError and OnLoginFailure delegates early. Network issues are common in games — show a reconnection banner rather than silently failing.

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Manual Connection

By default, the SDK auto-connects the WebSocket after login. For games with loading screens or lobbies where real-time events aren’t needed immediately, you can manage the connection manually.

Setup Manual Mode

Set bAutoEstablishSocketConnection = false in FCometChatAppSettings when configuring:

FCometChatAppSettings Settings;
Settings.Region = TEXT("us");
Settings.bAutoEstablishSocketConnection = false;
Chat->ConfigureWithSettings(TEXT("YOUR_APP_ID"), Settings);

Connect / Disconnect / Ping

Blueprint

• Connect Async — Establish the WebSocket after login
• Disconnect Async — Close the WebSocket (user stays authenticated)
• Ping Async — Verify the connection is alive

C++

// Connect when entering chat area
auto* Connect = UCometChatConnectAction::Connect(this);
Connect->OnSuccess.AddDynamic(this, &AMyActor::OnConnected);
Connect->OnFailure.AddDynamic(this, &AMyActor::HandleError);
Connect->Activate();

// Disconnect when leaving chat area
auto* Disconnect = UCometChatDisconnectAction::Disconnect(this);
Disconnect->OnSuccess.AddDynamic(this, &AMyActor::OnDisconnected);
Disconnect->Activate();

// Health check
auto* Ping = UCometChatPingAction::Ping(this);
Ping->OnSuccess.AddDynamic(this, &AMyActor::OnPingOk);
Ping->OnFailure.AddDynamic(this, &AMyActor::OnPingFailed);
Ping->Activate();

Query Connection State

ECometChatConnectionState State = Chat->GetConnectionStatus();
// Connected, Connecting, Disconnected, or FeatureThrottled

For full details on manual connection management, see Advanced Configuration.

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Next Steps

Typing Indicators

Send and receive typing state.

UI Components

Drop-in chat panel and button widgets.