Overview

Log users in and out of CometChat in your Unreal Engine project.

Create User

Before you log in a user, the user must exist in CometChat.

1. For proof of concept / MVPs: Create users via the CometChat Dashboard.
2. For production apps: Use the Create User REST API when your user signs up.

Sample Users

CometChat provides 5 pre-created users for testing: cometchat-uid-1, cometchat-uid-2, cometchat-uid-3, cometchat-uid-4, and cometchat-uid-5.

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Login using Auth Key

This authentication method is ideal for proof-of-concept development or early-stage apps. For production environments, we recommend using an Auth Token instead of an Auth Key for enhanced security.

Auth Flow

Blueprint

1. Get a reference to the CometChat Subsystem
2. Call the Login Async node
3. Wire the On Success and On Failure pins

Parameter	Type	Description
Uid	FString	The unique ID of the user to log in
Auth Key	FString	Your CometChat Auth Key

C++

#include "CometChatSubsystem.h"
#include "AsyncActions/CometChatLoginAction.h"

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

    // 1. Configure the SDK (do this once)
    UCometChatSubsystem* Chat = GetGameInstance()->GetSubsystem<UCometChatSubsystem>();
    Chat->Configure(TEXT("YOUR_APP_ID"), TEXT("us"));

    // 2. Bind real-time events before login
    Chat->OnMessageReceived.AddDynamic(this, &AMyActor::OnMessage);

    // 3. Login
    if (!Chat->IsLoggedIn())
    {
        auto* Login = UCometChatLoginAction::LoginAsync(
            this,
            TEXT("cometchat-uid-1"),
            TEXT("YOUR_AUTH_KEY")
        );
        Login->OnSuccess.AddDynamic(this, &AMyActor::OnLoginSuccess);
        Login->OnFailure.AddDynamic(this, &AMyActor::OnLoginFailed);
        Login->Activate();
    }
}

void AMyActor::OnLoginSuccess()
{
    UE_LOG(LogTemp, Log, TEXT("Login successful!"));
}

void AMyActor::OnLoginFailed(const FString& Error)
{
    UE_LOG(LogTemp, Error, TEXT("Login failed: %s"), *Error);
}

UID format: UIDs can be alphanumeric with underscores and hyphens. Spaces, punctuation, and other special characters are not allowed.

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Login using Auth Token

This is the recommended authentication method for production apps. Auth Tokens are generated server-side using the CometChat REST API and provide enhanced security since your Auth Key is never exposed on the client.

How Auth Tokens Work

1. Your backend calls the Create Auth Token REST API with the user’s UID
2. The API returns an Auth Token
3. Your backend sends the token to the Unreal client
4. The client calls LoginWithAuthTokenAsync with the token

Blueprint

1. Get a reference to the CometChat Subsystem
2. Call the Login With Auth Token Async node
3. Wire the On Success and On Failure pins

Parameter	Type	Description
Auth Token	FString	The auth token received from your backend

C++

#include "CometChatSubsystem.h"
#include "AsyncActions/CometChatLoginWithAuthTokenAction.h"

void AMyActor::LoginWithToken(const FString& AuthToken)
{
    UCometChatSubsystem* Chat = GetGameInstance()->GetSubsystem<UCometChatSubsystem>();

    if (!Chat->IsLoggedIn())
    {
        auto* Login = UCometChatLoginWithAuthTokenAction::LoginWithAuthTokenAsync(
            this,
            AuthToken
        );
        Login->OnSuccess.AddDynamic(this, &AMyActor::OnLoginSuccess);
        Login->OnFailure.AddDynamic(this, &AMyActor::OnLoginFailed);
        Login->Activate();
    }
}

void AMyActor::OnLoginSuccess()
{
    UE_LOG(LogTemp, Log, TEXT("Auth token login successful!"));
}

void AMyActor::OnLoginFailed(const FString& Error)
{
    UE_LOG(LogTemp, Error, TEXT("Auth token login failed: %s"), *Error);
}

Security: Never hardcode Auth Tokens in your client. Always fetch them from your backend at runtime.

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Check Login State

Before performing operations, you can check whether a user is currently logged in.

Blueprint

Call the Get Logged In User node on the CometChat Subsystem. It returns an FCometChatUser — if the Uid is empty, no user is logged in.

C++

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

if (Chat->IsLoggedIn())
{
    // User is authenticated — safe to send messages, fetch data, etc.
}

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Logout

Logs the current user out and disconnects the real-time WebSocket.

Blueprint

Call the Logout Async node on the CometChat Subsystem. Wire the On Success and On Failure pins.

C++

#include "AsyncActions/CometChatLogoutAction.h"

void AMyActor::PerformLogout()
{
    auto* Logout = UCometChatLogoutAction::LogoutAsync(this);
    Logout->OnSuccess.AddDynamic(this, &AMyActor::OnLogoutSuccess);
    Logout->OnFailure.AddDynamic(this, &AMyActor::OnLogoutFailed);
    Logout->Activate();
}

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Shutdown

To fully tear down the SDK (e.g., when your game is closing), call Shutdown on the Subsystem. This releases all resources and closes connections.

Blueprint

Call the Shutdown node on the CometChat Subsystem.

C++

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

You typically don’t need to call Shutdown manually — the Subsystem’s Deinitialize handles cleanup when the game instance is destroyed.

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Next Steps

Overview

Return to the SDK overview and architecture.

Send a Message

Send your first text message after logging in.

Real-Time Events

Listen for incoming messages and presence updates.