PubNub has developed a terminal client using Python and Curses to facilitate fast testing and debugging across multiple programming languages without leaving the terminal environment. This client supports features such as publishing messages, presence detection, and message history, allowing developers to interact with PubNub's API efficiently. Users can publish JSON messages, view them in a subscription window, and utilize auto-publishing for continuous testing. Despite some limitations, such as fixed window sizes, the terminal client offers a streamlined alternative to web-based debugging, enhancing productivity by integrating crucial functionalities directly into the terminal.