Tasmota
Universal firmware for ESP8266/ESP32 devices with web setup, OTA, automation, and local control.
Tasmota is an open-source firmware for ESP8266 and ESP32 based smart home devices. It provides a web UI for easy configuration, over-the-air updates, timer/rule automation, and local control via MQTT, HTTP, Serial, or KNX. It supports a vast array of sensors, switches, lights, and relays, with thousands of community-contributed device templates.