Shelly i4 Gen3 is a four-input, AC-powered Wi-Fi controller for turning ordinary wall switches or buttons into smart-home triggers. It has no switched load output; instead, its four inputs can activate scenes, run synchronised actions and trigger other Shelly, HTTP or MQTT-controlled devices.

Multi-click support provides up to 16 possible actions. Wi-Fi, Bluetooth for inclusion and gateway functions, scripting, webhooks, MQTT and an embedded web interface make it suitable for local automation as well as app-based control. It is designed to fit in a standard wall box behind a switch.