What is Sonoff-Tasmota?
It provides local control, MQTT and integration with home automation systems such as openHAB, Home Assistant and Domoticz.
You may find more information on the official GitHub page
You may also find relevant information on Tasmota at
If you are starting out and wish to have a relatively easy experience in developing your projects, then try the build-in web interface.
Example of Tasmota Web Interface
the Sonoff 4 Channel Pro MQTT Switch