Listen to the sound clip There is the user interface which you can see on the webpage or the UI where you can enter your name and log in. That is the Graphical User Interface (GUI). There is also the software interface where the application of a system needs to communicate with another piece of software. For example, it can make use of certain APIs or some other software services to send maybe an email or use http to pull certain content from website or send data for processing. from Cheerful - Sara (English United States) TTS Computer AI Voice: