Shelly is proud of their devices being:
- No hub neeeded
- Not required to be online
- Compatible all major hubs if you do want to connect them.
I do not work for Shelly. I just really like how I don't have to use an app for them and they're compatible with seemingly everything. I've bought the devices and I can do what I want with them.
I had owned two of their smart plugs for a couple of years and they decided to stop responding to resetting and could talk to them. Shelly support sent out two new plugs for me and asked for the defective ones back so they could troubleshoot them. Great service.
Just seems that privacy-centric people should be using privacy focused devices.
They are headquartered in Germany so very unlikely they'll go back on their offline compatibility anytime soon.
This should be possible to mount in the wall switch hole behind existing switch. You can still use normal switch or automate to your liking. There are dual devices for dual switch as well. I never used one, but planning to get some soon