Authentication - CometChat Docs

AI Integration Quick Reference

// Check if user is already logged in
val loggedInUser = CometChat.getLoggedInUser()

// Login with Auth Key (development only)
CometChat.login("UID", "AUTH_KEY", object : CometChat.CallbackListener<User?>() {
    override fun onSuccess(user: User?) { }
    override fun onError(e: CometChatException?) { }
})

// Login with Auth Token (production)
CometChat.login("AUTH_TOKEN", object : CometChat.CallbackListener<User?>() {
    override fun onSuccess(user: User?) { }
    override fun onError(e: CometChatException?) { }
})

// Logout
CometChat.logout(object : CometChat.CallbackListener<String>() {
    override fun onSuccess(p0: String?) { }
    override fun onError(p0: CometChatException?) { }
})

Required Credentials: App ID (from init), Auth Key (dev) or Auth Token (prod)
Get from: CometChat Dashboard → Your App → API & Auth Keys

After initializing the SDK, the next step is to authenticate your user. CometChat provides two login methods — Auth Key for quick development, and Auth Token for production — both accessed through the login() method.

Before You Log In

Create a User

A user must exist in CometChat before they can log in.

During development: Create users from the CometChat Dashboard. Five test users are already available with UIDs cometchat-uid-1 through cometchat-uid-5.
In production: Call the Create User REST API when a user signs up in your app.

We have set up 5 users for testing with UIDs: cometchat-uid-1, cometchat-uid-2, cometchat-uid-3, cometchat-uid-4, and cometchat-uid-5.

Check for an Existing Session

The SDK persists the logged-in user’s session locally. Before calling login(), always check whether a session already exists — this avoids unnecessary login calls.

Java
Kotlin

if (CometChat.getLoggedInUser() != null) {
    // User is already logged in — proceed to your app
}

if (CometChat.getLoggedInUser() != null) {
    // User is already logged in — proceed to your app
}

If getLoggedInUser() returns null, no active session exists and you need to call login().

CometChat.init() must be called before any other SDK method. Calling login(), sendMessage(), or registering listeners before init() will fail.

The CometChat SDK maintains the session of the logged-in user within the SDK. You do not need to call the login method for every session. Use CometChat.getLoggedInUser() to check for an existing session first.

This straightforward authentication method is ideal for proof-of-concept (POC) development or during the early stages of application development. For production environments, however, we strongly recommend using an Auth Token instead of an Auth Key to ensure enhanced security.

Auth Key is for development/testing only. In production, generate Auth Tokens on your server using the REST API and pass them to the client. Never expose Auth Keys in production client code.

Java
Kotlin

private String UID = "cometchat-uid-1";
private String authKey = "AUTH_KEY";

if (CometChat.getLoggedInUser() == null) {
    CometChat.login(UID, authKey, new CometChat.CallbackListener<User>() {
        @Override
        public void onSuccess(User user) {

        }

        @Override
        public void onError(CometChatException e) {

        }
    });
} else {
    // user already logged-in perform your action
}

val UID = "cometchat-uid-1"
val authKey = "AUTH_KEY"

if (CometChat.getLoggedInUser() == null) {
    CometChat.login(UID, authKey, object : CometChat.CallbackListener<User?>() {
        override fun onSuccess(user: User?) {}
        override fun onError(e: CometChatException?) {}
    })
} else {
    // user already logged-in perform your action
}

Parameter	Description
`UID`	The `UID` of the user that you would like to login
`authKey`	CometChat App Auth Key

After the user logs in, their information is returned in the User object. This advanced authentication procedure does not use the Auth Key directly in your client code, ensuring better security.

Create a User via the CometChat API when the user signs up in your app.
Create an Auth Token via the CometChat API for the new user every time the user logs in to your app.
Pass the Auth Token to your client and use it in the login() method.

Java
Kotlin

private String authToken = "AUTH_TOKEN";

CometChat.login(authToken, new CometChat.CallbackListener<User>() {
  @Override
  public void onSuccess(User user) {
    Log.d(TAG, "Login Successful : " + user.toString());
  }

  @Override
  public void onError(CometChatException e) {
    Log.d(TAG, "Login failed with exception: " + e.getMessage());
  }
});

val authToken:String="AUTH_TOKEN"

CometChat.login(authToken, object :CometChat.CallbackListener<User>(){
  override fun onSuccess(p0: User?) {
       Log.d(TAG, "Login Successful : " + p0?.toString())
    }

  override fun onError(p0: CometChatException?) {
      Log.d(TAG, "Login failed with exception: " +  p0?.message)
  }
})

Parameter	Description
authToken	Auth Token of the user you would like to login

After the user logs in, their information is returned in the User object.

Logout

You can use the logout() method to log out the user from CometChat. We suggest you call this method once your user has been successfully logged out from your app.

Java
Kotlin

CometChat.logout(new CometChat.CallbackListener<String>() {
  @Override
  public void onSuccess(String successMessage) {
    Log.d(TAG, "Logout completed successfully");
  }

  @Override
  public void onError(CometChatException e) {
    Log.d(TAG, "Logout failed with exception: " + e.getMessage());
  }
});

CometChat.logout(object : CometChat.CallbackListener<String>() {
  override fun onSuccess(p0: String?) {
    Log.d(TAG, "Logout completed successfully")
  }

  override fun onError(p0: CometChatException?) {
    Log.d(TAG, "Logout failed with exception: " + p0?.message)
  }
})

You can listen for login and logout events in real time using LoginListener. This is useful for updating UI state or triggering side effects when the auth state changes.

Callback	Description
`loginSuccess(User user)`	User logged in successfully. Provides the `User` object.
`loginFailure(CometChatException e)`	Login failed. Provides the exception with the reason.
`logoutSuccess()`	User logged out successfully.
`logoutFailure(CometChatException e)`	Logout failed. Provides the exception with the reason.

Add a Listener

Java
Kotlin

CometChat.addLoginListener("UNIQUE_ID", new CometChat.LoginListener() {
    @Override
    public void loginSuccess(User user) {
        Log.d("LoginListener", "loginSuccess " + user.toString());
    }

    @Override
    public void loginFailure(CometChatException e) {
        Log.d("LoginListener", "loginFailure " + e.getMessage());
    }

    @Override
    public void logoutSuccess() {
        Log.d("LoginListener", "logoutSuccess");
    }

    @Override
    public void logoutFailure(CometChatException e) {
        Log.d("LoginListener", "logoutFailure " + e.getMessage());
    }
});

CometChat.addLoginListener("UNIQUE_ID", object : LoginListener() {
    override fun loginSuccess(user: User) {
        Log.d("LoginListener", "loginSuccess $user")
    }

    override fun loginFailure(e: CometChatException) {
        Log.d("LoginListener", "loginFailure " + e.message)
    }

    override fun logoutSuccess() {
        Log.d("LoginListener", "logoutSuccess")
    }

    override fun logoutFailure(e: CometChatException) {
        Log.d("LoginListener", "logoutFailure " + e.message)
    }
})

Remove a Listener

Java
Kotlin

CometChat.removeLoginListener("UNIQUE_ID");

CometChat.removeLoginListener("UNIQUE_ID")

Always remove login listeners when they’re no longer needed (e.g., in onDestroy()). Failing to remove listeners can cause memory leaks and duplicate event handling.

Next Steps

Send a Message

Start sending text, media, and custom messages to users and groups

User Management

Retrieve and manage users in your application

Connection Status

Monitor the SDK connection state in real time

Key Concepts

Understand core CometChat concepts and terminology

​Before You Log In

​Create a User

​Check for an Existing Session

​Login using Auth Key

​Login using Auth Token

​Logout

​Login Listener

​Add a Listener

​Remove a Listener

​Next Steps

Send a Message

User Management

Connection Status

Key Concepts

Before You Log In

Create a User

Check for an Existing Session

Login using Auth Key

Login using Auth Token

Logout

Login Listener

Add a Listener

Remove a Listener

Next Steps