ESPEasy
http://www.esp8266.nu/index.php/ESPEasy
Just flash the 4096 sized firmware image to the ESP whilst connected via micro USB to your PC and then connect to the ESP_0 wireless network that the ESP hosts afterwards. I've got various sensors, relays and display screens connected together via ESPEasy - communicating via MQTT to Pimatic and via HTTP to Thingspeak.
Useful links:-
https://forum.pimatic.org/topic/1367/es ... ver-mqtt/2