I have a standard wall switch connected to an input on a Shelly relay, call it A. I have a second Shelly relay (call it B) across the house that has a light connected to the relay output.

Using the Shelly Cloud software, can the switch input on A control the relay on B?

  • 1
    what did you have to do to pair up the wall switch with Shelly A ? ... do the same with Shelly B
    – jsotola
    Commented Mar 9, 2020 at 6:13
  • 1
    That's not the way Shelly relays work. It's a single box with a relay output and a switch input. You can wire up a standard wall switch to the switch input. The relay can be controlled by software or the wall switch. You can also "detatch" the switch input from the relay so that the input can control something else. But I haven't figured out how to program the Shelly cloud software to connect the switch input to something else.
    – longneck
    Commented Mar 9, 2020 at 13:45
  • I clarified the working. Shelly calls their units "relays".
    – longneck
    Commented Mar 9, 2020 at 13:49
  • via MQTT I think you can achieve this
    – cgmckeever
    Commented Jul 11, 2020 at 1:48

3 Answers 3


Yes, just using the built-in local software.

Background: Shelly relays can be sent http commands to switch them on and off. This is documented at https://shelly.cloud/documents/developers/ddd_communication.pdf

First, on relay B, find the local network address of the device. This is in Settings -> Device Information, and will be something like 192.168.x.y where x and y are two numbers between 0 and 254. Make a note of these numbers.

Now, on relay A, go into Actions and find the "Button switched on URL" and "Button switched off URL" lines.

Enable these, and add a URL. It will be something like: http://192.168.x.y/relay/0/?turn=on to switch the other device on.

If you don't want relay A to change anything connected directly, you can change its button type to "Detached Switch"

  • I wish this was slightly easier: the app knows all the devices, so it can automatically figure out the IP address of device B and change necessary settings on device A. Though maybe such configuration is advanced enough that most users trying to achieve it, would be able to follow the manual process you described. Commented Jul 24, 2022 at 7:26

Here's how I did it: https://youtu.be/yNspcmSY-60

I Got the Shelly IP & MAC addresses from my router's "Connected Devices" page. Then I reserved (or you can make static routes) for the Shelly's least my router changes the assigned address on restart and mess up my scripts.

My Scripts are: In Actions

http://192.168.0.(Your Address Here)/relay/0?turn=on

http://192.168.0.(Your Address Here)/relay/0?turn=off

IMPORTANT: When you start your Shelly's for the first time UPDATE THE FIRMWARE. I didn't and did some configurations on the Shelly's web-server that really looked wrong. Then after a firmware update everything got way better but I had to do a factory reset and start from scratch because my first script was still there but I couldn't find it to edit/delete it.


I used the following 2x Actions in my "Detached" 1Plus to control my Dimmer2 ON/OFF state remotely and it still doesn't work. I can hear the 1Plus clicking ON/OFF but the Dimmer2 output is unaffected. Any thoughts? "" is the address of my Dimmer2.

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