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.

Join Session

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