Well, as usual I'm late to the party. This weekend I come to love Tasmota, a basically ready to run firmware for ESP8266 MCUs and many products, which use the ESP8266. It didn't click until I tried it for myself. Firstly I reflashed 2 el-cheapo Wifi-plugs with Tasmota and then I flashed a Witty cloud module and connected a SR04 distance and a SI7021 temperature sensor (below). This will become something like https://sourd.io powered by Tasmota and MQTT. No code written, all declarative.