PubNub is a real-time communication platform that enables developers to build applications that require instant data updates. It provides a set of APIs and services that facilitate messaging, presence, and data synchronization across devices. This makes it ideal for applications like chat, live updates, and collaborative tools. With PubNub, developers can easily integrate features such as push notifications and user presence tracking into their applications. The platform supports various programming languages and frameworks, allowing for flexibility in development. Its global infrastructure ensures low-latency communication, making it suitable for applications with a large user base.