Developer Jul 26, 2022

How to Use Video Call API to Build an iOS Live Video Call App

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With the continuous improvement of device performance and network quality, more and more audio and video call scenarios have been applied, and video call API has also been applied more and more.

What capabilities can the video call API provide?

With the increasing demand for video call API, there are more and more companies providing video call API, but the functions provided are similar.

The capabilities provided by the video call API mainly include the following:

  1. Call invitation
  2. Voice and Video call
  3. Offline push function
  4. Call UI and interaction

Below is a live video call app built using ZEGOCLOUD's video call API.

video call api Demo

Tall to an Expert ↓

What is ZEGOCLOUD's video call API?

ZEGOCLOUD's video call API uses a layered architecture. Details are as shown in the figure below:

video call api architecture

ZEGOCLOUD's video call API provides two different SDKs for you: the CallUIKit and the Call SDK.

CallUIKit: Provide a complete live video call UI, you only need to call the call interface and hang up the interface where you need to complete the call process.

Call SDK: Provides the underlying logic of live video calls, such as audio and video management, call management, network status management, etc. You only need to focus on the implementation of the upper-layer custom UI and call the corresponding interactive interface to complete the call process.

How to use ZEGOCLOUD's Video call API

Step 1. Create a ZEGOCLOUD account

create an account
Create an account

Step 2. Create a new project

creata a project
Create a project

Step 3. Create a Firebase project

Create a Firebase project in the Firebase console. For more details, see Firebase Documentation.

create firebase
Create a Firebase project

Step 4. Deploy the Firebase Cloud Functions

ZEGO Call uses the Firebase Cloud Functions as the business server by default, we recommend you activate and deploy it before integrating the ZEGOCall SDK.

Create a new Realtime Database in Firebase.

create firebase
Create a new Realtime Database

Edit the rules of the Realtime Database by adding the following:

  "rules": {
        ".read": "auth.uid != null",
        ".write": "auth.uid != null",
Edit the rules of the Realtime Database

Install the CLI via npm.

npm install -g firebase-tools
Install the CLI
Install the CLI 

Run the firebase login to log in via the browser and authenticate the firebase tool.

firebase login
Run the firebase login

Run firebase init functions. The tool gives you an option to install dependencies with npm. It is safe to decline if you want to manage dependencies in another way, though if you do decline you'll need to run npm install before emulating or deploying your functions.

init functions
Run firebase init functions

Download the Cloud function sample code.

Download file
Download the Cloud function sample code

Copy the firebase.json, functions\index.js files and functions\token04 folder in the sample code to your cloud function project, overwrite files with the same name.

Copy the firebase file
copy file
Copy the firebase file
  1. Modify the index.js file, fill in the AppID and ServerSecret you get from ZEGOCLOUD Admin Console correctly.
write appID
Modify the index.js
  1. In Firebase CLI, run the firebase deploy --only functions command to deploy the cloud functions.
run the firebase deploy --only functions

Step 5. Copy file into the project

To integrate the ZEGOCallUIKit automatically with CocoaPods, do the following:

Download the Sample codes, and copy the ZEGOCallUIKit and ZEGOCall folders to your project directory (if you have no project, create a new one).

Download the Sample codes

Open Terminal, navigate to your project directory, run the pod init command to create a Podfile, and then add the following to the file.

pod 'ZegoExpressEngine'

pod 'FirebaseAuth'
pod 'GoogleSignIn'
pod 'Firebase/Database'
pod 'Firebase/Analytics'
pod 'Firebase/Crashlytics'
pod 'Firebase/Messaging'
pod 'Firebase/Functions'
pod install

In Terminal, navigate to the directory where the Podfile locates, and run the pod install command.

pod install

Restart the Xcode, and open the newly generated .workspace file.

Step 6. Add permissions

Permissions can be set as needed.

  1. Open Xcode, select the target object, and then click Info > Custom iOS Target Properties.
Permissions can be set as needed
  1. Click the Add button (+) to add camera and microphone permissions.

Privacy-Camera Usage Description

Privacy-Microphone Usage Description

Permissions can be set as needed

Select the target project, select Sign&Capabilities > Capability, search for Background Modes and make a double click.

Background Modes

Check the following options in Background Modes.

Background Modes

Enable the Push Notification feature.

Enable the Push Notification

Download the config file GoogleService-Info.plist of firebase, and add it to your project. To get the config file, refer to How to get the config file?.

add GoogleService-Info.plist
add GoogleService-Info.plist

Set up the URL Types: Fill in the URL Schemes with the REVERSED_CLIENT_ID field in the GoogleService-Info.plist file.

Set up the URL Types

Initialize the ZEGOCallUIKit

To initialize the ZEGOCallUIKit, get the CallManager instance, pass the AppID of your project.

// Initialize the ZEGOCallUIKit. We recommend you call this method when the application starts.
// YOUR_APP_ID is the AppID you get from ZEGOCLOUD Admin Console. 
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    CallManager.shared.initWithAppID(YOUR_APP_ID) { result in
        // Callback for the result of init. 
    return true

To receive callbacks, set the corresponding delegate to self.

CallManager.shared.delegate = self

User login

ZEGO Call does not provide user management capabilities yet. You will need to have users log in to Firebase and then call the setLocalUser method to set user information to CallUIKit based on the login result.

Firebase provides multiple login authentication modes. The following uses Google login as an example.
For more modes, refer to the Firebase official.

var userID: String?
var userName: String?

GIDSignIn.sharedInstance.signIn(with: config, presenting: self) { user, error in
       guard let token = user?.authentication.idToken,
             error == nil
          else {

            let credential = GoogleAuthProvider.credential(withIDToken: token, accessToken: "")
        Auth.auth().signIn(with: credential) { result, error in
            guard let user = result?.user else {
            self.userID = user.uid
            self.userName = user.displayName

// Set local user info.
CallManager.shared.setLocalUser(userID, userName: userName)

Get a Token

ZEGO Call implements the voice and video call feature using the RTC SDK. The caller and called user join the same room and the stream publishing and stream playing start upon the call gets connected. Therefore, to make an outbound call, you will need to provide a token for the RTC SDK for validation. For details, see Use Tokens for authentication.

Before making or accepting an outbound call, you will need to get a Token from the Firebase Cloud Functions.

private func getTokenFromServer(_ userID: String,
                                    _ effectiveTimeInSeconds: Int,
                                    callback: @escaping TokenCallback) {
        let functions = Functions.functions()
        let data: [String: Any] = [
            "id": userID, /// The userID of the current user.
            "effective_time": effectiveTimeInSeconds /// The valid period of the Token.
        functions.httpsCallable("getToken").call(data) { result, error in
            if let error = error as NSError? {
                print("[* Firebase] Get token failed: \(error)")
            guard let dict = result?.data as? [String: Any],
                  let token = dict["token"] as? String
            else {

To set a Token to the token property of the CallManager, implement the agent-owned callback getRTCToken of the TokenProvider.

// Get and set the Token.
// userID refres to the ID of the logged in user.
func getRTCToken(_ callback: @escaping TokenCallback) {
        guard let userID = CallManager.shared.localUserInfo?.userID else {
        let token: String? = result.success
        getTokenFromServer(userID, effectiveTimeInSeconds) { result in
            switch result {
            case .success(let token):
            guard let callback = callback else { return }
            case .failure(let error):
            guard let callback = callback else { return }


Make outbound calls

To make an outbound voice call, call the callUser method and set the type parameter to CallType.voice.

// toUserID refers to the ID of the user you want call. 
// CallType.voice indicates that you make a voice call.
CallManager.shared.callUser(userInfo, callType: .voice) { result in
    // Callback for the result of make a voice call. 

To make an outbound video call, call the callUser method and set the type parameter to

// userInfo refers to the user info(ID and name) of the user you want call. 
// indicates that you make a video call.
CallManager.shared.callUser(userInfo, callType: .video) { result in
    // Callback for the result of make a video call. 

After making a call, the CallUIKit shows the UI of the current state automatically for both the callee and caller (integrated the CallUIKit is required), and, you can operate on the UI for further operations.

The following displays when the caller calls the method to make a call (make a voice call for illustration)

calling ui

The following black pop-up prompts when the callee receives an incoming call (make a voice call for illustration)

callee receives an incoming call

Upload logs

When you encounter problems when using your app, call the uploadLog  method to upload logs for us to locate and help you faster.

CallManager.shared.uploadLog { result in
    // Callback for the result of upload SDK log.

Deinitialize the ZEGOCallUIKit

After finishing using the ZEGO Call, call the unInit method to deinitialize the SDK.




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