> ## Documentation Index
> Fetch the complete documentation index at: https://cometchat-013b37f0.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# User Management

When a user logs into your app, you need to programmatically login the user into CometChat. But before you log in the user to CometChat, you need to create the user.

**When a user registers in your app**

1. You add the user details in your database
2. You create a user in CometChat

**When a user logs into your app**

1. You log in the user to your app
2. You [log in the user to CometChat](/sdk/android/3.0/authentication) (programmatically)

## Creating a user

Ideally, user creation should take place at your backend. You can refer our Rest API to learn more about [creating a user](https://api-explorer.cometchat.com/reference/creates-user) and use the appropriate code sample based on your backend language.

However, if you wish to create users on the fly, you can use the `createUser()` method. This method takes a `User` object and the `API Key` as input parameters and returns the created `User` object if the request is successful.

For more details on the fields present in the User class, please check [this](/sdk/android/3.0/users-user-management#user-class)

<Tabs>
  <Tab title="Java">
    ```java theme={null}
    String apiKey = "AUTH_KEY"; // Replace with your API Key.
    User user = new User();
    user.setUid("user1"); // Replace with your uid for the user to be created.
    user.setName("Kevin"); // Replace with the name of the user

    CometChat.createUser(user, apiKey, new CometChat.CallbackListener<User>() {
      @Override
      public void onSuccess(User user) {
        Log.d("createUser", user.toString());
      }

      @Override
      public void onError(CometChatException e) {
        Log.e("createUser", e.getMessage());
      }
    });
    ```
  </Tab>

  <Tab title="Kotlin">
    ```kotlin theme={null}
    val apiKey = "API_KEY" // Replace with your API Key.
    val user = User()
    user.uid = "user1" // Replace with your uid for the user to be created.
    user.name = "Kevin" // Replace with the name of the user

    CometChat.createUser(user, apiKey, object : CometChat.CallbackListener<User>() {
      override fun onSuccess(user: User) {
        Log.d("createUser", user.toString())
      }

      override fun onError(e: CometChatException) {
        Log.e("createUser", e.message)
      }
    })
    ```
  </Tab>
</Tabs>

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

## Updating a user

Updating a user similar to creating a user should ideally be achieved at your backend using the Restful APIs. For more information, you can check the [update a user](https://api-explorer.cometchat.com/reference/update-user) section. However, this can be achieved on the fly as well using the `updateUser()` method. This method takes a `User` object and the API Key as inputs and returns the updated `User` object on successful execution of the request.

<Tabs>
  <Tab title="Java">
    ```java theme={null}
    String apiKey = "AUTH_KEY"; // Replace with your API Key.
    User user = new User();
    user.setUid("user1"); // Replace with your uid for the user to be updated.
    user.setName("Kevin Fernandez"); // Replace with the name of the user

    CometChat.updateUser(user, apiKey, new CometChat.CallbackListener<User>() {
      @Override
      public void onSuccess(User user) {
        Log.d("updateUser", user.toString());
      }

      @Override
      public void onError(CometChatException e) {
        Log.e("updateUser", e.getMessage());
      }
    });
    ```
  </Tab>

  <Tab title="Kotlin">
    ```kotlin theme={null}
    val apiKey = "API_KEY" // Replace with your API Key.
    val user = User()
    user.uid = "user1" // Replace with your uid for the user to be updated.
    user.name = "Kevin Fernandez" // Replace with the name of the user

    CometChat.updateUser(user, apiKey, object : CometChat.CallbackListener<User>() {
      override fun onSuccess(user: User) {
        Log.d("updateUser", user.toString())
      }

      override fun onError(e: CometChatException) {
        Log.e("updateUser", e.message)
      }
    })
    ```
  </Tab>
</Tabs>

Please make sure the `User` object provided to the `updateUser()` method has the `UID` of the user to be updated set.

## Updating logged-in user

Updating a logged-in user is similar to updating a user. The only difference being this method does not require an AuthKey. This method takes a `User` object as input and returns the updated `User` object on the successful execution of the request.

<Tabs>
  <Tab title="Java">
    ```java theme={null}
    User user = new User();
    user.setName("Andrew Joseph"); 

    CometChat.updateCurrentUserDetails(user, new CometChat.CallbackListener<User>() {
      @Override
      public void onSuccess(User user) {
        Log.d(TAG, user.toString());
      }

      @Override
      public void onError(CometChatException e) {
        Log.d(TAG, e.getMessage());
      }
    });
    ```
  </Tab>

  <Tab title="Kotlin">
    ```kotlin theme={null}
    val user = User()
    user.name = "Andrew Joseph"

    CometChat.updateCurrentUserDetails(user, object : CallbackListener<User>() {
      override fun onSuccess(user: User) {
        Log.d(TAG, user.toString())
      }

      override fun onError(e: CometChatException) {
        Log.d(TAG, e.message)
      }
    })
    ```
  </Tab>
</Tabs>

By using the `updateCurrentUserDetails()` method one can only update the logged-in user irrespective of the UID passed. Also, it is not possible to update the role of a logged-in user.

## Deleting a user

Deleting a user can only be achieved via the Restful APIs. For more information please check the [delete a user](https://api-explorer.cometchat.com/reference/delete-user)section.

## User Class

| Field         | Editable                                            | Information                                                          |
| ------------- | --------------------------------------------------- | -------------------------------------------------------------------- |
| uid           | specified on user creation. Not editable after that | Unique identifier of the user                                        |
| name          | Yes                                                 | Display name of the user                                             |
| avatar        | Yes                                                 | URL to profile picture of the user                                   |
| link          | Yes                                                 | URL to profile page                                                  |
| role          | Yes                                                 | User role of the user for role based access control                  |
| metadata      | Yes                                                 | Additional information about the user as JSON                        |
| status        | No                                                  | Status of the user. Could be either online/offline                   |
| statusMessage | Yes                                                 | Any custom status message that needs to be set for a user            |
| lastActiveAt  | No                                                  | The unix timestamp of the time the user was last active.             |
| hasBlockedMe  | No                                                  | A boolean that determines if the user has blocked the logged in user |
| blockedByMe   | No                                                  | A boolean that determines if the logged in user has blocked the user |
| tags          | Yes                                                 | A list of tags to identify specific users                            |