Join Session

Join a call session using one of two approaches: the quick start method with a session ID, or the advanced flow with manual token generation for more control.

Overview

The CometChat Calls SDK provides two ways to join a session:

Approach	Best For	Complexity
Join with Token	Most use cases - recommended approach	Low - Two-step process
Generate Token Separately	Custom token management, pre-generation, caching	Medium - Separate token handling

Both approaches require a container element in your HTML where the call interface will be rendered.

Container Setup

Add a container element to your HTML where the call interface will be rendered:

<div id="call-container" style="width: 100%; height: 100vh;"></div>

The call UI will be dynamically rendered inside this container when you join the session.

Generate Token

Generate a call token for the session. Each token is unique to a specific session and user combination.

const sessionId = "SESSION_ID";

try {
  const result = await CometChatCalls.generateToken(sessionId);
  console.log("Token generated:", result.token);
  // Use the token to join the session
} catch (error) {
  console.error("Token generation failed:", error.errorDescription);
}

Parameter	Type	Description
`sessionId`	String	Unique identifier for the call session

The method returns an object with:

Property	Type	Description
`token`	String	The generated call token

The generateToken() method uses the auth token of the currently logged-in user. Ensure a user is logged in before calling this method.

Use the generated token to join the session along with your call settings and container element.

const container = document.getElementById("call-container");

const callSettings = {
  sessionType: "VIDEO",
  layout: "TILE",
  startAudioMuted: false,
  startVideoPaused: false,
};

const result = await CometChatCalls.joinSession(callToken, callSettings, container);

if (result.error) {
  console.error("Failed to join session:", result.error);
} else {
  console.log("Joined session successfully");
}

Parameter	Type	Description
`callToken`	String	Previously generated call token
`callSettings`	Object	Configuration for the session (see Session Settings)
`container`	HTMLElement	Container element for the call UI

The method returns an object with:

Property	Type	Description
`data`	undefined	Undefined on success
`error`	Object \| null	Error details if join failed

Complete Example

const sessionId = "SESSION_ID";
const container = document.getElementById("call-container");

// Step 1: Generate token
try {
  const tokenResult = await CometChatCalls.generateToken(sessionId);
  
  // Step 2: Configure session settings
  const callSettings = {
    sessionType: "VIDEO",
    layout: "TILE",
    startAudioMuted: false,
    startVideoPaused: false,
  };

  // Step 3: Join session
  const joinResult = await CometChatCalls.joinSession(
    tokenResult.token, 
    callSettings, 
    container
  );

  if (joinResult.error) {
    console.error("Failed to join session:", joinResult.error);
  } else {
    console.log("Joined session successfully");
  }
} catch (error) {
  console.error("Error:", error);
}

All participants joining the same call must use the same session ID.

Error Handling

Common errors when joining a session:

Error Code	Description
`ERROR_SDK_NOT_INITIALIZED`	SDK not initialized - call `init()` first
`ERROR_AUTH_TOKEN_MISSING`	User not logged in or auth token invalid
`ERROR_SESSION_ID_MISSING`	Session ID is null or empty
`VALIDATION_ERROR`	Invalid call settings

​Overview

​Container Setup

​Generate Token

​Join Session

​Complete Example

​Error Handling

Overview

Container Setup

Generate Token

Join Session

Complete Example

Error Handling