ctrlspace
// The most local-friendly relay on the market

Shelly

Small relay and dimmer modules that fit behind an existing switch plate, with a documented local HTTP and MQTT API and no requirement for a cloud account at all. When the wall has to stay exactly as it is, this is usually the answer.

Why we use Shelly

  • A fully documented local API. No cloud account is needed for the device to work, and that is the company's design intent rather than a loophole.
  • It fits behind existing switch plates, so an interior that was chosen carefully does not have to change.
  • It keeps the existing physical switch working, including old toggle and momentary switches.
  • Built-in power measurement on many models, which makes per-circuit energy monitoring straightforward.
  • Newer generations support Matter and MQTT out of the box.

Where we do not, and why

  • It needs physical space in the back box. Some Singapore switch boxes are shallow and simply will not take a module.
  • It is Wi-Fi, so a house full of Shellys adds up on the network. We mix them with Zigbee rather than using them everywhere.
  • There is no screen or indicator, so the wall gives no feedback beyond the light itself.

Pros and cons at a glance

Pros
  • Genuinely local, with a documented API
  • Keeps existing switch plates and switches
  • Power metering built into many models
  • Wide model range including dimmers, roller shutters and DIN-rail units
  • Matter and MQTT support on current generations
Cons
  • Needs depth in the back box
  • Wi-Fi, so device count has to be managed
  • No physical status indication
  • Installation is inside the wall, so it is an electrician job

The technical position

Main protocol
Wi-Fi, with Matter and MQTT on current generations
Local control
Yes, fully, with a documented HTTP API
Vendor hub needed
No
Home Assistant support
Excellent, native integration
Singapore availability
Available through specialist suppliers

Where it fits in a CtrlSpace build

Our default whenever the existing switch plates must stay - a condo with a designer finish, a landed home with brass plates, or any situation where replacing twenty switches would change how a room looks. Also our first choice for retrofitting a gate, a water heater or a pump.

// Frequently asked

Shelly, answered plainly

Will a Shelly fit in my switch box?

Usually, but not always. Singapore back boxes vary in depth and a shallow one with existing wiring can be too tight. We check on the site visit rather than discovering it on installation day.

Does Shelly need an account or a subscription?

No. The device works entirely on your local network with a documented API. A cloud account is optional and we do not use it.
// 9 more in this category

See others in switches, relays and sensors

Zigbee Aqara The workhorse of most Singapore builds Zigbee · Wi-Fi Sonoff Cheap, capable, and best used on your own terms Zigbee · Wi-Fi Tuya / Smart Life Half the market, and two very different halves Zigbee ThirdReality Cheap Zigbee that mostly behaves Wi-Fi · ESPHome Athom Devices that ship already local Wi-Fi · ESPHome Everything Presence mmWave presence done properly Zigbee Schneider Electric Wiser Electrical-grade build, ecosystem strings attached Z-Wave Aeotec Solid Z-Wave, wrong side of the frequency map Z-Wave Fibaro Beautifully made, hard to justify here

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