Shelly i4 Gen3 vs Shelly Plus 2PM

The Shelly Plus 2PM wins overall. It controls two circuits with per-channel energy monitoring, adds cover and interlock mode for shutters, supports dry and wet contacts and DC loads, and lists a full protection set. The Shelly i4 Gen3 is cheaper and adds Matter and HomeKit, but it has no relay.

Relay channels. The Shelly Plus 2PM has two, with interlock so they can safely drive a motor in both directions, plus metering on each. The Shelly i4 Gen3 has none, offering four inputs instead, so it reads switches rather than powering anything.

The Shelly Plus 2PM, whose cover mode is built for shutters, blinds and gates and prevents both directions being energized at once. The Shelly i4 Gen3 can read the up and down buttons on the wall, but it needs a relay module like the Plus 2PM to actually move the motor.

Only the Shelly i4 Gen3, which supports both, alongside Alexa, Google Home and Home Assistant. The Shelly Plus 2PM works with Alexa, Google Home, SmartThings and Home Assistant, and can run entirely locally, but it has no Matter or HomeKit support.

Buy the Shelly Plus 2PM if you need two metered channels or want to automate a roller shutter, blind or gate with interlock protection. It supports dry and wet contacts, lists overheating, overvoltage, overcurrent and overpower protection, runs locally with Home Assistant and carries a 3-year warranty.

Buy the Shelly i4 Gen3 if you want to keep your existing wall switches and use them as smart triggers, with Matter and Apple HomeKit support and four flexible inputs. It is small, quick and inexpensive, and it belongs alongside relay modules rather than instead of them.