I have two separate native apps—Swift on iOS and Kotlin on Android—and I need full Sinch SDK integration across both. The goal is to add three core capabilities: voice calling, video calling, and in-app messaging, all wrapped in a clean user interface that feels identical on the two platforms. At this stage I’m still weighing whether to gate the functions behind authentication. If we do go that route, email-and-password login is the preferred method, so I’ll look to you for technical guidance on the easiest way to wire that into Sinch’s user management or my own back end. Feel free to suggest best-practice flows or alternatives before we lock it in. Here’s what I expect you to deliver: • Swift and Kotlin code that boots the Sinch client, registers the user, and exposes voice, video, and messaging calls through simple view controllers / activities. • Incoming and outgoing call screens that handle push notifications, background modes, and interruption events correctly on both OSs. • A lightweight messaging view with read receipts and typing indicators, using Sinch’s REST or socket layer as appropriate. • Clear setup instructions plus any helper scripts or configuration files so I can reproduce your build in Xcode and Android Studio. The apps are already live, so your work will live inside existing repositories; I’ll grant access as soon as we begin. If you’ve shipped Sinch-powered apps before, mention it—that experience will pay off when we hit platform-specific quirks.