Authentication - CometChat Docs

AI Integration Quick Reference

// Check existing session
let user = CometChat.getLoggedInUser()

// Login with Auth Key (development only)
CometChat.login(UID: "cometchat-uid-1", authKey: "AUTH_KEY", onSuccess: { user in
  print("Logged in: \(user.stringValue())")
}, onError: { error in
  print("Login failed: \(error.errorDescription)")
})

// Login with Auth Token (production)
CometChat.login(authToken: "AUTH_TOKEN", onSuccess: { user in
  print("Logged in: \(user.stringValue())")
}, onError: { error in
  print("Login failed: \(error.errorDescription)")
})

// Logout
CometChat.logout(onSuccess: { _ in
  print("Logged out")
}, onError: { error in
  print("Logout failed: \(error.errorDescription)")
})

Create users via: Dashboard (testing) | REST API (production) Test UIDs: cometchat-uid-1 through cometchat-uid-5

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.

How It Works

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.

You can also create users from the client side using createUser() (development only):

Swift
Objective-C

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

let newUser = User(uid: uid, name: name)

CometChat.createUser(user: newUser, apiKey: authKey, onSuccess: { (user) in
  print("User created: \(user.stringValue())")
}) { (error) in
  print("Error: \(String(describing: error?.description))")
}

NSString *authKey = @"AUTH_KEY";
User *newUser = [[User alloc] initWithUid:@"user1" name:@"Kevin"];

[CometChat createUserWithUser:newUser apiKey:authKey onSuccess:^(User * user) {
  NSLog(@"User created: %@", [user stringValue]);
} onError:^(CometChatException * error) {
  NSLog(@"Error: %@", [error errorDescription]);
}];

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.

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

If getLoggedInUser() returns nil, 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.

Swift
Objective-C

let uid = "cometchat-uid-1"
let authKey = "AUTH_KEY"

if CometChat.getLoggedInUser() == nil {
  CometChat.login(UID: uid, authKey: authKey, onSuccess: { (user) in
    print("Login successful: " + user.stringValue())
  }) { (error) in
    print("Login failed with error: " + error.errorDescription)
  }
}

NSString *uid = @"cometchat-uid-1";
NSString *authKey = @"AUTH_KEY";

[CometChat loginWithUID:uid authKey:authKey onSuccess:^(User * user) {
  NSLog(@"Login successful: %@", [user stringValue]);
} onError:^(CometChatException * error) {
  NSLog(@"Login failed with error: %@", [error errorDescription]);
}];

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

On success, the callback returns 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().

Swift
Objective-C

let authToken = "AUTH_TOKEN"

if CometChat.getLoggedInUser() == nil {
  CometChat.login(authToken: authToken, onSuccess: { (user) in
    print("Login successful: " + user.stringValue())
  }) { (error) in
    print("Login failed with error: " + error.errorDescription)
  }
}

NSString *authToken = @"AUTH_TOKEN";

[CometChat loginWithAuthToken:authToken onSuccess:^(User * user) {
  NSLog(@"Login successful: %@", [user stringValue]);
} onError:^(CometChatException * error) {
  NSLog(@"Login failed with error: %@", [error errorDescription]);
}];

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

On success, the callback returns 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.

Swift
Objective-C

CometChat.logout(onSuccess: { (response) in
  print("Logout completed successfully")
}) { (error) in
  print("Logout failed with error: " + error.errorDescription)
}

[CometChat logoutOnSuccess:^(NSString * response) {
  NSLog(@"Logout completed successfully");
} onError:^(CometChatException * error) {
  NSLog(@"Logout failed: %@", [error errorDescription]);
}];

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

Ringing Calls

Implement voice and video calls with ringing

​How It Works

​Before You Log In

​Create a User

​Check for an Existing Session

​Login with Auth Key

​Login with Auth Token

​Logout

​Next Steps

Send Messages

User Management

Connection Status

Ringing Calls

How It Works

Before You Log In

Create a User

Check for an Existing Session

Login with Auth Key

Login with Auth Token

Logout

Next Steps