> ## Documentation Index
> Fetch the complete documentation index at: https://cometchat-22654f5b-docs-rn-guide-message-privately.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Setup

> Setup — CometChat documentation.

## Get your Application Keys

[Signup for CometChat](https://app.cometchat.com) and then:

1. Create a new app
2. Head over to the **API & Auth Keys** section and note the **Auth Key**, **App ID** & **Region**

## Add the CometChat Dependency

### NPM

<Tabs>
  <Tab title="JavaScript">
    ```bash theme={null}
    npm install @cometchat-pro/chat@2.4.1 --save
    ```
  </Tab>
</Tabs>

Then, import the `CometChat` object wherever you want to use CometChat.

<Tabs>
  <Tab title="JavaScript">
    ```javascript theme={null}
    import { CometChat } from "@cometchat-pro/chat";
    ```
  </Tab>
</Tabs>

### HTML (via CDN)

Include the CometChat JavaScript library in your HTML code.

<Tabs>
  <Tab title="HTML">
    ```html theme={null}
    <script type="text/javascript" src="https://unpkg.com/@cometchat-pro/chat@2.4.1/CometChat.js"></script>
    ```
  </Tab>
</Tabs>

## Initialize CometChat

The `init()` method initialises the settings required for CometChat. The `init()` method takes the below parameters:

1. appID - You CometChat App ID
2. appSettings - An object of the AppSettings class can be created using the AppSettingsBuilder class. The region field is mandatory and can be set using the `setRegion()` method.

The `AppSettings` class allows you to configure two settings:

* **Region**: The region where you app was created.
* [Presence Subscription](/sdk/javascript/2.0/user-presence)

You need to call `init()` before calling any other method from CometChat. We suggest you call the `init()` method on app startup, preferably in the `index.js` file.

<Tabs>
  <Tab title="JavaScript">
    ```javascript theme={null}
    let appID = "APP_ID";
    let region = "APP_REGION";
    let appSetting = new CometChat.AppSettingsBuilder()
                      .subscribePresenceForAllUsers()
                      .setRegion(region)
                      .build();
    CometChat.init(appID, appSetting).then(
    () => {
      console.log("Initialization completed successfully");
    }, error => {
      console.log("Initialization failed with error:", error);
    }
    );
    ```
  </Tab>
</Tabs>

Make sure you replace the `APP_ID` with your CometChat **App ID** and `APP_REGION` with your **App Region** in the above code.

| Parameter  | Description                         |
| ---------- | ----------------------------------- |
| appID      | CometChat App ID                    |
| appSetting | An object of the AppSettings class. |