Shelly Dimmer Gen4

Quick verdict

The Dimmer Gen4 is what Shelly sells in place of the discontinued Dimmer 2, the retired Shelly I most wanted to see replaced properly. It sits behind your existing switch, dims trailing-edge up to 150 W of LED, and adds Zigbee 3.0 and Matter to Wi-Fi and Bluetooth; Home Assistant can take it through the Shelly integration, Zigbee2MQTT or Matter, all local. One radio profile runs at a time. The wiring detail is where I would slow down: Shelly's 230 V documentation allows no-neutral use with a bypass, but its US documentation says the dimmer works only with a neutral while the US store title says No Neutral, so confirm the exact SKU against your box before ordering. I haven't run this one; the notes come from the spec sheet, the Home Assistant integration docs and what other owners report.

Standout: Hides in the wall box behind your existing switch like the Dimmer 2 did, and adds Zigbee 3.0 and Matter to the Wi-Fi and Bluetooth radios.

Notes last checked Sep 6, 2026.

Compatibility snapshot

Why it stands out

• trailing-edge dimming for dimmable LEDs up to 150 W, incandescent and halogen up to 200 W, and electronic transformers up to 200 W
• keeps the local Shelly extras: web interface, RPC API, MQTT, scripting, two switch inputs for momentary or toggle wall switches
• Zigbee profile pairs with Zigbee2MQTT, and the default Matter profile works with Apple Home, Google Home and Alexa
• fits behind an existing switch, so the wall hardware you already like stays

Reasons to hesitate

• the two regional models differ on wiring: Shelly's 230 V documentation allows no-neutral use with a bypass under 20 W, while the US documentation says the trailing-edge dimmer works only with a neutral, even though the US store title says No Neutral; confirm for your exact SKU before buying
• one radio profile at a time: it ships in Matter and five presses of the button switch it to Zigbee, dropping the Wi-Fi firmware features
• Zigbee2MQTT had no device page for the US S4DM-0A102US when I checked, only an external definition without power readings, and Zigbee OTA updates are not available yet
• in-wall install with a small module in a crowded box is not a beginner job, and no power measurement without a neutral

Best for

• Dimmer 2 owners who need a replacement or want the same hidden approach on another circuit
• retrofits where the existing switch plate has to stay
• Home Assistant users who want a fully local dimmer with Wi-Fi or Zigbee as they prefer

Avoid if

• you want a finished, decorator-style smart dimmer rather than a module behind the switch
• your US box has no neutral and you were counting on no-neutral operation
• you need Zigbee mode with full power monitoring on the US model today

Privacy and local-control notes

Same local story as every Gen2-and-later Shelly: a built-in web interface, RPC API, MQTT and scripting with no account, or Zigbee to your own coordinator, or Matter. Shelly cloud is optional.

Home Assistant support: supported · integration path: Shelly (official core integration, Local Push) over Wi-Fi with the local RPC API or MQTT; Zigbee2MQTT in the Zigbee profile (the 230 V S4DM-0A101WWL has a device page, the US S4DM-0A102US relied on an external definition when I checked); Matter integration in the default Matter profile.

Buying reality check

Price notes: US version $49.99 and in stock on us.shelly.com on 2026-09-06. The 230 V version is sold through shelly.com and EU retailers. Mid band, about double a plug-in smart plug but in line with other in-wall dimmer modules.

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