There are broadly two types of smart switches available. Touch/mechanical smart switches with generally wifi as a communication protocol and small relays that goes behind existing switch boards. They usually use zigbee or z-wave or wifi as a communication protocol. While it is recommended to use z-wave/zigbee as they are more robust but wifi switches are cheaper than them. I recently got my home done from a guy ,my friend knows in gurgaon. I am pretty sure he does projects PAN india. I got 8 z-wave relays from fibaro and 1 zwave gateway. So far it works great. Great thing is it is not dependent on cloud for local control which means i can control all my appliances even if my internet goes down as long as i am in same wifi network. And all of this is wireless so there was no civil work.