Ajax polling or Web Sockets (socket.io) for client-server communication.

[countable]

The application needs a way for each terminal to always display the most recent data in the UI. Either of these methods will work. We are leaning towards ajax polling for an MVP because it's a little simpler (avoids another component). If Web Sockets are used, we would also need to find a way to hook into database writes and selectively broadcast them from the server to update the clients. This is an extra piece of logic not needed with Ajax polling.