iOS Calling UI SDK

The iOS Calling UI SDK wraps Apple's native calling infrastructure to deliver a full incoming-call screen experience in your iOS app with minimal code. When a VoIP push arrives, the SDK presents the familiar iOS system-level calling UI — the same one users see for regular phone calls — and routes accept, reject, hold, and end actions back to your app via callback delegates. Combined with the iOS UI Kit, you can enable complete app-to-app audio/video calling in under five minutes.

The SDK's core class is EnxCallKit. You create a single instance in the class where your app handles incoming VoIP push notifications, then call reportIncomingCall to trigger the system calling UI. The SDK handles the full UI lifecycle and calls back your delegate methods when the user interacts with the screen.

When loading the calling UI, you must wrap the operation in an iOS background task to ensure the system gives your app enough time to present the screen before being suspended.

Before integrating the iOS Calling UI SDK, ensure:

• VoIP background mode enabled — In Xcode, go to your target's Signing & Capabilities tab and add the Background Modes capability. Enable Voice over IP. This allows your app to receive PushKit VoIP notifications while in the background and launch the calling UI.
• Notification service in place — EnableX does not provide a push notification service. You must integrate Apple PushKit (VoIP push) with your server to deliver incoming-call signals to the device. The SDK cannot present its UI without an incoming push trigger.

Via CocoaPods

Open your Podfile and add the SDK pod, then install:

pod 'Enx_CallKit_iOS'

cd /path/to/your-project/
pod install

Manual Installation

1. Download Enx_CallKit_iOS.framework_1.0.3.zip using the button above and unzip it.
2. In Xcode, open your project navigator and drag Enx_CallKit_iOS.framework into the Frameworks, Libraries, and Embedded Content section of your target.
3. Set the embed option to Embed & Sign.

1. Import and Initialise

Go to the class where you receive VoIP push notifications (typically your PKPushRegistryDelegate implementation). Import the framework and create an EnxCallKit instance:

import Enx_CallKit_iOS

class CallNotificationHandler: NSObject, PKPushRegistryDelegate, EnxCallKitDelegate {

    var callManager: EnxCallKit?

    func setup() {
        callManager = EnxCallKit(self)
        // self: sets the callback delegate
    }
}

2. Report an Incoming Call

When a VoIP push arrives, use reportIncomingCall to present the system calling UI. Wrap it in a background task so iOS does not suspend the app before the UI appears:

func pushRegistry(_ registry: PKPushRegistry,
                  didReceiveIncomingPushWith payload: PKPushPayload,
                  for type: PKPushType,
                  completion: @escaping () -> Void) {

    // Begin a background task — iOS must not suspend the app during UI presentation
    let bgTask = UIApplication.shared.beginBackgroundTask(expirationHandler: nil)

    let callerName = payload.dictionaryPayload["callerName"] as? String ?? "Unknown"
    let hasVideo   = payload.dictionaryPayload["hasVideo"]   as? Bool   ?? false

    callManager?.reportIncomingCall(
        uuid:       UUID(),
        callerName: callerName,
        hasVideo:   hasVideo
    ) { _ in
        // End the background task once the calling UI has loaded
        UIApplication.shared.endBackgroundTask(bgTask)
        completion()
    }
}

3. End a Call Programmatically

To dismiss the calling UI from your code (for example when a session ends on the remote side), call endCall(). This closes the system calling screen immediately:

callManager?.endCall()

Implement the EnxCallKitDelegate protocol in the class you passed as self during initialisation. The SDK calls these methods based on user interaction with the calling screen:

extension CallNotificationHandler: EnxCallKitDelegate {

    func callAnswer() {
        // Start the EnableX video session
        VideoSessionManager.shared.connect(roomId: roomId, token: token)
    }

    func callReject() {
        // Notify the remote caller and clean up
        signallingServer.sendReject(to: callerId)
    }

    func callTimeOut() {
        // 45 seconds elapsed with no response — call auto-dismissed
        signallingServer.sendMissedCall(to: callerId)
    }

    func callEnd() {
        // Session ended — return to idle
        VideoSessionManager.shared.disconnect()
    }

    func callHold() {
        // Put media on hold
        VideoSessionManager.shared.hold()
    }
}

• iOS UI Kit — Full audio/video room UI built on top of the EnableX iOS SDK. Pair with the Calling UI SDK for a complete calling experience.
• iOS Video SDK — The underlying SDK for building custom video UIs.
• Apple CallKit documentation — The system framework that the iOS Calling UI SDK is built upon.