A MIDI controller is a device that allows musicians and producers to create and manipulate music using MIDI (Musical Instrument Digital Interface) signals. It typically features keys, pads, knobs, and sliders that can control various aspects of music software or hardware instruments. These controllers do not produce sound on their own; instead, they send commands to other devices, such as synthesizers or digital audio workstations (DAWs). This makes them essential tools for modern music production, enabling users to play, record, and edit music efficiently.