Easiest control method for custom device?

I want to make a set of dial zone heating pad controllers “smart”. I’m thinking esp8266. They are already more advanced than the normal controllers, so just leaving them “on” and using a wifi plug won’t work. What’s the easiest, reverse phone lookup least equipment way to control them? Don’t want to do smart things, or openhab/home assistant type setup. Don’t need control nba reddit outside the local wifi. Would like to be able to ask Google Assistant to at least turn it on. Least I’m thinking is maybe it hosts it’s own webserver with a simple interface. Maybe an API that I can integrate with something? Looking for options. Thanks

In my opinion MQTT is an easy and flexible way to do that.
I’ve just finished making my intercom smart.

My project uses Homie-esp8266 to take care of all the fundamental stuff like managing connections,the configuration portal and MQTT communications.

Voice control can be done by creating a virtual device in Homey (switch) exposing that to Google Assitant.

Other libraries that can the same are WifiManager, ESP8266-IOT, iotWebConfig etc, etc