> ## Documentation Index
> Fetch the complete documentation index at: https://cometchat-22654f5b-docs-v6-beta2-flutter-uikit.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# Authentication
> Learn how to create users, log in with Auth Key or Auth Token, and manage user sessions in CometChat React Native SDK.
**Quick Reference** - Login with Auth Key (dev) or Auth Token (production):
```javascript theme={null}
// Auth Key login (development only)
const user = await CometChat.login("USER_UID", "AUTH_KEY");
// Auth Token login (recommended for production)
const user = await CometChat.login("AUTH_TOKEN");
// Check existing session
const loggedInUser = await CometChat.getLoggedinUser();
```
## Create User
Before you log in a user, you must add the user to CometChat.
1. **For proof of concept/MVPs**: Create the user using the [CometChat Dashboard](https://app.cometchat.com).
2. **For production apps**: Use the CometChat [Create User API](https://api-explorer.cometchat.com/reference/creates-user) to create the user when your user signs up in your app.
**Sample Users:** 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`.
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.
## Login using Auth Key
**Security Warning:** This straightforward authentication method is ideal for proof-of-concept (POC) development or during the early stages of application development. For production environments, we strongly recommend using an [Auth Token](#login-using-auth-token) instead of an Auth Key to ensure enhanced security.
```javascript theme={null}
var UID = "UID";
var authKey = "AUTH_KEY";
// Check if user is already logged in before calling login
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("Something went wrong", error);
}
);
```
```typescript theme={null}
var UID: string = "cometchat-uid-1",
authKey: string = "AUTH_KEY";
// Check if user is already logged in before calling login
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 Occured", error);
}
);
```
| Parameter | 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.
**On Success** — Returns a User object:
**User Object:**
| Parameter | Type | Description | Sample Value |
| --------------- | ------- | --------------------------------------------------- | ----------------------------------------------------------------------- |
| `uid` | string | Unique identifier of the user | `"cometchat-uid-2"` |
| `name` | string | Display name of the user | `"George Alan"` |
| `authToken` | string | Authentication token for the session | `"cometchat-uid-2_17713124898af10df254d51ef6ffc14e79955ac0"` |
| `avatar` | string | URL to user's avatar image | `"https://assets.cometchat.io/sampleapp/v2/users/cometchat-uid-2.webp"` |
| `status` | string | Current online status | `"online"` |
| `role` | string | User's role | `"default"` |
| `lastActiveAt` | number | Unix timestamp of last activity | `1771311515` |
| `hasBlockedMe` | boolean | Whether this user has blocked the logged-in user | `false` |
| `blockedByMe` | boolean | Whether logged-in user has blocked this user | `false` |
| `deactivatedAt` | number | Unix timestamp if user is deactivated (0 if active) | `0` |
| `tags` | array | Tags associated with the user | `[]` |
## Login using Auth Token
This advanced authentication procedure does not use the Auth Key directly in your client code, thus ensuring safety.
[Create a User](https://api-explorer.cometchat.com/reference/creates-user) via the CometChat API when the user signs up in your app.
[Create an Auth Token](https://api-explorer.cometchat.com/reference/create-authtoken) 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 theme={null}
var authToken = "AUTH_TOKEN";
// Check if user is already logged in before calling login
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("Something went wrong", error);
}
);
```
```typescript theme={null}
var authToken: string = "AUTH_TOKEN";
// Check if user is already logged in before calling login
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 Occured", error);
}
);
```
| 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 on the `Promise` resolved.
**On Success** — Returns a User object:
**User Object:**
| Parameter | Type | Description | Sample Value |
| --------------- | ------- | --------------------------------------------------- | ----------------------------------------------------------------------- |
| `uid` | string | Unique identifier of the user | `"cometchat-uid-2"` |
| `name` | string | Display name of the user | `"George Alan"` |
| `authToken` | string | Authentication token for the session | `"cometchat-uid-2_17713124898af10df254d51ef6ffc14e79955ac0"` |
| `avatar` | string | URL to user's avatar image | `"https://assets.cometchat.io/sampleapp/v2/users/cometchat-uid-2.webp"` |
| `status` | string | Current online status | `"online"` |
| `role` | string | User's role | `"default"` |
| `lastActiveAt` | number | Unix timestamp of last activity | `1771311515` |
| `hasBlockedMe` | boolean | Whether this user has blocked the logged-in user | `false` |
| `blockedByMe` | boolean | Whether logged-in user has blocked this user | `false` |
| `deactivatedAt` | number | Unix timestamp if user is deactivated (0 if active) | `0` |
| `tags` | array | Tags associated with the user | `[]` |
## 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.
```javascript theme={null}
CometChat.logout().then(
() => {
console.log("Logout completed successfully");
},
(error) => {
console.log("Logout failed with exception:", error);
}
);
```
```typescript theme={null}
CometChat.logout().then(
(loggedOut: Object) => {
console.log("Logout completed successfully");
},
(error: CometChat.CometChatException) => {
console.log("Logout failed with exception:", error);
}
);
```
**On Success** — Returns a success message:
| Parameter | Type | Description | Sample Value |
| --------- | ------ | ------------------- | --------------------------------- |
| `message` | string | Logout confirmation | `"Logout completed successfully"` |
* Always check for an existing session with `getLoggedinUser()` before calling `login()`
* Use Auth Token (not Auth Key) in production environments
* Generate Auth Tokens server-side and never expose your REST API Key in client code
* Call `logout()` when the user logs out of your app to clean up the CometChat session
* Handle login errors gracefully and provide user-friendly error messages
* **Login fails with "UID not found":** Ensure the user has been created in CometChat before attempting login
* **Auth Token expired:** Generate a new Auth Token from your server and retry login
* **Session persists after logout:** Ensure `logout()` completes successfully before redirecting
* **Multiple login calls:** Use `getLoggedinUser()` to prevent redundant login attempts
## Next Steps
Listen for real-time login and logout events
Start sending text, media, and custom messages
Track real-time online/offline status of users
Add pre-built UI components to your app