Key Concepts

Learn key CometChat JavaScript SDK concepts, including apps, users, auth keys, roles, and groups.

CometChat Dashboard

The CometChat Dashboard enables you to create new apps (projects) and manage your existing apps.

How many apps to create?

Ideally, you should create two apps- one for development and one for production. And you should use a single app irrespective of the number of platforms.

Do not create separate apps for every platform; if you do, your users on different platforms will not be able to communicate with each other!

• For every app, a unique App ID is generated. This App ID will be required when integrating CometChat within your app.
• Along with the App ID, you will need to create an Auth Key (from the Dashboard) which can be used for user authentication.

Auth & Rest API Keys

You can generate two types of keys from the dashboard.

Type	Privileges	Recommended Use
Auth Key	The Auth Key can be used to create & login users.	In your client side code (during development)
Rest API Key	The Rest API Key can be used to perform any CometChat operation.	In your server side code

Users

A user is anyone who uses CometChat.

UID

• Each user is uniquely identified using UID.
• The UID is typically the primary ID of the user from your database.

UID can be alphanumeric with underscore and hyphen. Spaces, punctuation and other special characters are not allowed.

Auth Token

• A single user can have multiple auth tokens. The auth tokens should be per user per device.
• It should be generated by API call ideally, via server to server call. The auth token should then be given to CometChat for login.
• An Auth Token can only be deleted via dashboard or using REST API.

Authentication

To allow a user to use CometChat, the user must log in to CometChat.

CometChat does not handle user management. You must handle user registration and login at your end. Once the user is logged into your app/site, you can log in the user to CometChat programmatically. So the user does not ever directly login to CometChat.

CometChat does not handle friends management. If you want to associate friends with your users, you must handle friends management in your app. Once two users are friends (i.e. they have accepted each other as friends), then you can associate them as friends in CometChat.

Typical Workflow

Your App	Your Server	CometChat
User registers in your app	You store the user information in your database (e.g. ID, name, email, phone, location etc. in users table)	You add the user to CometChat (only ID & name) using the Rest API
User logs in to your app	You verify the credentials, login the user and retrieve the user ID	You log in the user to CometChat using the same user ID programmatically
User sends a friend request	You display the request to the potential friend	No action required
User accepts a friend request	You display the users as friends	You add both the users as friends using the Rest API

User Roles

A role is a category for grouping similar users. For example, group premium users with the role “Premium” to filter users or enable/disable features conditionally.

Authentication

CometChat does not handle user registration or friends management — you handle that in your app, then log users into CometChat programmatically.

API Keys

You can generate two types of keys from the CometChat Dashboard:

Type	Privileges	Recommended Use
Auth Key	Create & login users	Client-side code (development only)
REST API Key	Perform any CometChat operation	Server-side code only

Never expose your REST API Key in client-side code. Use Auth Tokens for production authentication.

Auth Tokens

Auth Tokens are secure, per-user credentials for production use:

• A single user can have multiple auth tokens (one per device)
• Generate tokens server-side via the REST API
• Tokens can only be deleted via the Dashboard or REST API

Authentication Flow

Create your apps in the CometChat Dashboard — each app gets a unique App ID required for SDK initialization. Ideally, create two apps — one for development and one for production. Use a single app regardless of the number of platforms; if you create separate apps per platform, your users won’t be able to communicate across them.

Your App	Your Server	CometChat
User registers	Store user info in your database	Create user via REST API (UID & name)
User logs in	Verify credentials, retrieve user ID	Log in user programmatically with UID
User sends friend request	Display request to potential friend	No action required
User accepts friend request	Display users as friends	Add both users as friends via REST API

Groups

A group enables multiple users to communicate on a particular topic or interest. Each group is uniquely identified using a GUID (Group Unique Identifier).

• The GUID is typically the primary ID of the group from your database
• GUID can be alphanumeric with underscore and hyphen only

Group Types

Type	Visibility	Participation
Public	All users	Any user can join
Password	All users	Users with valid password can join
Private	Members only	Users must be invited (auto-joined)

Member Scopes

Once a user joins a group, they become a member with one of three scopes:

Scope	Default	Privileges
Admin	Group creator	Full control: manage members, change scopes, kick/ban anyone, update/delete group
Moderator	—	Moderate: change participant scopes, kick/ban participants, update group
Participant	All other members	Basic: send & receive messages and calls

Message Categories

Every message belongs to one of these categories:

Category	Types	Description
message	text, image, video, audio, file	Standard messages
custom	Developer-defined	Custom data (e.g., location, polls)
action	groupMember, message	System-generated (joins, edits, deletes)
call	audio, video	Call-related messages

For more details, see the Message Structure and Hierarchy guide.

Glossary

Term	Definition	Learn More
UID	Unique User Identifier — alphanumeric string you assign to each user	Users Overview
GUID	Group Unique Identifier — alphanumeric string you assign to each group	Groups Overview
Auth Key	Development-only credential for quick testing. Never use in production	Authentication
Auth Token	Secure, per-user token generated via REST API. Use in production	Authentication
REST API Key	Server-side credential for REST API calls. Never expose in client code	CometChat Dashboard
Receiver Type	Specifies if a message target is a user or group	Send Message
Scope	Group member scope: admin, moderator, or participant	Change Member Scope
Listener	Callback handler for real-time events (messages, presence, calls, groups)	All Real-Time Listeners
Conversation	A chat thread between two users or within a group	Retrieve Conversations
Metadata	Custom JSON data attached to users, groups, or messages	Send Message
Tags	String labels for categorizing users, groups, conversations, or messages	Message Filtering
RequestBuilder	Builder pattern class for constructing filtered/paginated queries	Message Filtering
AppSettings	Configuration object for initializing the SDK (App ID, Region, presence)	Setup SDK
Transient Message	Ephemeral message not stored on server (typing indicators, live reactions)	Transient Messages

---

Next Steps

Setup SDK

Install and initialize the CometChat SDK

Authentication

Log users in and manage auth tokens

Send Messages

Send your first text or media message

Groups Overview

Create and manage group conversations