MIDI (Musical Instrument Digital Interface) is a communication protocol that allows electronic musical devices, such as effects pedals, multi-effects processors, amplifiers, and synthesizers, to interact and control each other. In the world of guitar effects, MIDI is often used to switch presets, control parameters in real time, and synchronise effects with other gear, offering seamless integration and expanded functionality.

Many modern pedals, like the Strymon Timeline, Eventide H9, and Boss ES-8, feature MIDI In/Out connectivity, enabling players to control multiple effects with a single footswitch or external MIDI controller. This makes MIDI an essential tool for musicians looking to simplify their rig, automate complex setups, or integrate their pedalboard with digital workstations and live performance systems.