Authentication - CometChat Docs

Create User

Before you log in a user, you must add the user to CometChat.

For proof of concept/MVPs: Create the user using the CometChat Dashboard.
For production apps: Use the CometChat Create User API to create the user when your user signs up in your app.

We have setup 5 users for testing having UIDs: cometchat-uid-1, cometchat-uid-2, cometchat-uid-3, cometchat-uid-4 and cometchat-uid-5.

Once initialization is successful, you will need to log the user into CometChat using the login() method. We recommend you call the CometChat login method once your user logs into your app. The login() method needs to be called only once.

The CometChat SDK maintains the session of the logged-in user within the SDK. Thus you do not need to call the login method for every session. You can use the CometChat.getLoggedinUser() method to check if there is any existing session in the SDK. This method should return the details of the logged-in user. If this method returns null, it implies there is no session present within the SDK and you need to log the user into CometChat.

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 AuthToken instead of an Auth Key to ensure enhanced security.

TypeScript
JavaScript

let authKey: string = "AUTH_KEY";
let uid: string = "user1";
let name: string = "Kevin";

let user: CometChat.User = new CometChat.User(uid);
user.setName(name);

CometChat.createUser(user, authKey).then(
(user: CometChat.User) => {
console.log("User created:", user);
},
(error: CometChat.CometChatException) => {
console.log("Error:", error);
}
);

let authKey = "AUTH_KEY";
let uid = "user1";
let name = "Kevin";

let user = new CometChat.User(uid);
user.setName(name);

CometChat.createUser(user, authKey).then(
  (user) => {
    console.log("User created:", user);
  },
  (error) => {
    console.log("Error:", error);
  }
);

createUser() with Auth Key is for development only. In production, create users server-side via the REST API. See User Management for full details.

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 and keeps your app responsive.

const user = await CometChat.getLoggedinUser();
if (user) {
  // User is already logged in — proceed to your app
}

If getLoggedinUser() returns null, no active session exists and you need to call login(). Auth Key login is the simplest way to get started. Pass a UID and your Auth Key directly from the client.

Auth Keys are meant for development and testing only. For production, use Auth Token login instead. Never ship Auth Keys in client-side code.

TypeScript

const UID: string = "cometchat-uid-1";
const authKey: string = "AUTH_KEY";

CometChat.getLoggedinUser().then(
(user: CometChat.User) => {
if (!user) {
CometChat.login(UID, authKey).then(
(user: CometChat.User) => {
console.log("Login Successful:", { user });
},
(error: CometChat.CometChatException) => {
console.log("Login failed with exception:", { error });
}
);
}
},
(error: CometChat.CometChatException) => {
console.log("Some Error Occurred", { error });
}
);

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

After the user logs in, their information is returned in the User object on Promise resolved. This advanced authentication procedure does not use the Auth Key directly in your client code thus ensuring safety.

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 and save the token in your database.
Load the Auth Token in your client and pass it to the login() method.

JavaScript

const UID = "cometchat-uid-1";
const authKey = "AUTH_KEY";

CometChat.getLoggedinUser().then(
  (user) => {
    if (!user) {
      CometChat.login(UID, authKey).then(
        (user) => {
          console.log("Login Successful:", { user });
        },
        (error) => {
          console.log("Login failed with exception:", { error });
        }
      );
    }
  },
  (error) => {
    console.log("Some Error Occurred", { error });
  }
);

Alternatively, you can use the async/await syntax:

const UID = "cometchat-uid-1";
const authKey = "AUTH_KEY";

try {
  const loggedInUser = await CometChat.getLoggedinUser();
  if (!loggedInUser) {
    const user = await CometChat.login(UID, authKey);
    console.log("Login Successful:", { user });
  }
} catch (error) {
  console.log("Login failed with exception:", { error });
}

Parameter	Description
UID	The UID of the user to log in
authKey	Your CometChat Auth Key

On success, the Promise resolves with a User object containing the logged-in user’s details. Auth Token login keeps your Auth Key off the client entirely. Your server generates a token via the REST API and passes it to the client.

Create the user via the REST API when they sign up (first time only).
Generate an Auth Token on your server and return it to the client.
Pass the token to login().

TypeScript
JavaScript

const authToken: string = "AUTH_TOKEN";

CometChat.getLoggedinUser().then(
(user: CometChat.User) => {
if (!user) {
CometChat.login(authToken).then(
(user: CometChat.User) => {
console.log("Login Successful:", { user });
},
(error: CometChat.CometChatException) => {
console.log("Login failed with exception:", { error });
}
);
}
},
(error: CometChat.CometChatException) => {
console.log("Some Error Occurred", { error });
}
);

const authToken = "AUTH_TOKEN";

CometChat.getLoggedinUser().then(
  (user) => {
    if (!user) {
      CometChat.login(authToken).then(
        (user) => {
          console.log("Login Successful:", { user });
        },
        (error) => {
          console.log("Login failed with exception:", { error });
        }
      );
    }
  },
  (error) => {
    console.log("Some Error Occurred", { error });
  }
);

Alternatively, you can use the async/await syntax:

const authToken = "AUTH_TOKEN";

try {
  const loggedInUser = await CometChat.getLoggedinUser();
  if (!loggedInUser) {
    const user = await CometChat.login(authToken);
    console.log("Login Successful:", { user });
  }
} catch (error) {
  console.log("Login failed with exception:", { error });
}

Parameter	Description
authToken	Auth Token generated on your server for the user

On success, the Promise resolves with a User object containing the logged-in user’s details.

Logout

Call logout() when your user logs out of your app. This clears the local session.

TypeScript
JavaScript

CometChat.logout().then(
  (loggedOut: Object) => {
    console.log("Logout completed successfully");
  },
  (error: CometChat.CometChatException) => {
    console.log("Logout failed with exception:", { error });
  }
);

CometChat.logout().then(
  () => {
    console.log("Logout completed successfully");
  },
  (error) => {
    console.log("Logout failed with exception:", { error });
  }
);

Alternatively, you can use the async/await syntax:

try {
  await CometChat.logout();
  console.log("Logout completed successfully");
} catch (error) {
  console.log("Logout failed with exception:", { error });
}

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(event)`	User logged in successfully. Provides the `User` object.
`loginFailure(event)`	Login failed. Provides a `CometChatException`.
`logoutSuccess()`	User logged out successfully.
`logoutFailure(event)`	Logout failed. Provides a `CometChatException`.

Add a Listener

TypeScript
JavaScript

const listenerID: string = "UNIQUE_LISTENER_ID";
CometChat.addLoginListener(
    listenerID,
    new CometChat.LoginListener({
        loginSuccess: (user: CometChat.User) => {
            console.log("LoginListener :: loginSuccess", user);
        },
        loginFailure: (error: CometChat.CometChatException) => {
            console.log("LoginListener :: loginFailure", error);
        },
        logoutSuccess: () => {
            console.log("LoginListener :: logoutSuccess");
        },
        logoutFailure: (error: CometChat.CometChatException) => {
            console.log("LoginListener :: logoutFailure", error);
        }
    })
);

let listenerID = "UNIQUE_LISTENER_ID";
CometChat.addLoginListener(
    listenerID,
    new CometChat.LoginListener({
        loginSuccess: (e) => {
            console.log("LoginListener :: loginSuccess", e);
        },
        loginFailure: (e) => {
            console.log("LoginListener :: loginFailure", e);
        },
        logoutSuccess: () => {
            console.log("LoginListener :: logoutSuccess");
        },
        logoutFailure: (e) => {
            console.log("LoginListener :: logoutFailure", e);
        }
    })
);

Remove a Listener

CometChat.removeLoginListener("UNIQUE_LISTENER_ID");

Always remove login listeners when they’re no longer needed (e.g., on component unmount or page navigation). Failing to remove listeners can cause memory leaks and duplicate event handling.

Next Steps

Send Messages

Send your first text, media, or custom message

User Management

Create, update, and delete users programmatically

Connection Status

Monitor the SDK connection state in real time

All Real-Time Listeners

Complete reference for all SDK event listeners

​Create User

​Login using Auth Key

​Check for an Existing Session

​Login with Auth Key

​Login using Auth Token

​Login with Auth Token

​Logout

​Login Listener

​Add a Listener

​Remove a Listener

​Next Steps

Send Messages

User Management

Connection Status

All Real-Time Listeners

Create User

Login using Auth Key

Check for an Existing Session

Login with Auth Key

Login using Auth Token

Login with Auth Token

Logout

Login Listener

Add a Listener

Remove a Listener

Next Steps