The Phoenix Framework is an open-source web development framework written in the programming language Elixir. It is designed to create scalable and maintainable applications, leveraging the capabilities of the Erlang virtual machine. Phoenix emphasizes real-time features, making it suitable for applications that require instant updates, such as chat applications or live dashboards. One of the key features of Phoenix is its use of the MVC (Model-View-Controller) architecture, which helps organize code and separate concerns. Additionally, Phoenix includes built-in support for WebSockets, allowing for real-time communication between the server and clients. This makes it a popular choice for developers looking to build modern web applications efficiently.