Shelly i4 Gen3 vs Shelly Plus 1

The Shelly Plus 1 wins overall because it can actually switch a circuit, with a 16A relay, dry and wet contact modes, DC support and documented overheating protection. The Shelly i4 Gen3 is cheaper and adds Matter and Apple HomeKit, but it is an input-only module.

The relay. The Shelly Plus 1 has one, rated for 16A AC or 10A DC, with the option of isolated dry contacts. The Shelly i4 Gen3 has none, offering four inputs instead, so it triggers automations rather than powering or switching anything itself.

Yes, and it is a natural pairing. Put the Shelly i4 Gen3 behind a multi-gang switch plate to read the buttons, and let a Shelly Plus 1 do the switching at the light, boiler or gate. Both are small enough to sit in a back box and both run locally with Home Assistant.

Only the Shelly i4 Gen3, which supports Matter and Apple HomeKit along with Alexa, Google Home and Home Assistant. The Shelly Plus 1 has neither Matter nor HomeKit, so it reaches Apple's ecosystem only through a bridge such as Home Assistant.

Buy the Shelly Plus 1 if you need a dependable single-channel relay with dry contact isolation for a gate, garage or boiler, or want to switch a 30V DC circuit. It is UL listed, lists overheating protection, runs without a cloud account and comes with a 3-year warranty.

Buy the Shelly i4 Gen3 if you want to keep your existing wall switches working while using them as smart triggers, or to bring buttons and dry-contact sensors into scenes. It supports Matter and HomeKit, doubles as a Bluetooth gateway, and hides behind a switch plate.