> ## 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.

# Calling

> Calling — CometChat documentation.

Calling is a core feature of CometChat.

## Prerequisites

1. CometChat Core SDK installed.
2. Performed the steps mentioned in the [Setup](/sdk/android/2.0/setup) guide

<Note>
  Add the CometChat Calls Dependency

  v2.4+ onwards, Voice & Video Calling functionality has been moved to a separate library. Please add the following dependency to your app-level `build.gradle` file in case you plan on using the Voice and Video Calling feature.\
  dependencies \{ implementation 'com.cometchat:pro-android-calls-sdk:2.1.1' }
</Note>

CometChat allows two mechanisms for calling

1. **Direct Calling**
2. **Default Calling**

## Direct Calling

Direct Calling allows you to start the call/conference sessions directly with the session Id of your choice. All the users joining the same session Id are connected to the same call/conference. For more information on Direct Calling, please visit the [Direct Calling docs](/sdk/android/2.0/direct-calling).

## Default Calling

The second approach that CometChat allows is to implement the entire calling flow where one user initiates a call/conference and other user/users who want to be a part of the call accept/reject the call. All the users that accept the call are connected to the same session. For more information on Default Calling, please visit the [Default Calling docs.](/sdk/android/2.0/default-calling)