I had my fair share of endeavors with closed and open home automation solutions and this one really hit it off. openHAB is an amazingly flexible center for your smart home, regardless if you are playing around with ESP8266's or driving a whole KNX installation. It's open source and the ~200 add-ons can talk to nearly everything out there, from Z-Wave over Alexa and IFTTT, your Tesla car and up to whatever you get onto MQTT. One warning though: "With great power comes great responsibility" ;) openHAB is not a point and shoot adventure. Setting up the SmartHome takes a few minutes. But it's totally worth it! Happy Hacking!