This tutorial provides a comprehensive guide on creating an iOS mobile chat app using Swift 5 and the PubNub platform, which facilitates real-time messaging and message storage. The tutorial covers setting up the app using Xcode, implementing PubNub's key features like Publish/Subscribe for real-time communication, and Storage & Playback for message persistence. It explains how to design the user interface with necessary views and navigation controls, handle user connections to chat channels, and manage message events using PubNub's API. The app supports sending and receiving messages instantly, storing message history, and retrieving past messages, ensuring that users can seamlessly leave and return to the chat. The tutorial also includes instructions on configuring PubNub with API keys, setting message retention times, and subscribing to channels, ultimately resulting in a functional chat application that can serve as a foundation for further development or integration into larger apps.