Pusher 3 is a popular open-source library designed for real-time web applications. It enables developers to easily implement features like live notifications, chat systems, and collaborative tools by facilitating real-time communication between clients and servers. The library supports various programming languages and frameworks, making it versatile for different development environments. One of the key features of Pusher 3 is its ability to handle WebSocket connections, which allows for efficient data transfer without the need for constant polling. This results in faster updates and a smoother user experience. Additionally, Pusher 3 offers built-in support for scaling applications, ensuring that they can handle a growing number of users seamlessly.