See wiki for more info https://github.com/1technophile/OpenMQTTGateway/wiki

These gateways can be integrated with home automation systems like Openhab or Home assistant thanks to the MQTT protocol.

A list of supported 433mhz devices is available here: https://community.home-assistant.io/t/433tomqttto433-gateway-device-list/7819

examples_with_gpio_usage/433toMQTTto433nFan_ESP8266 - ESP8266 gateway between 433mhz and a fan's remote control, from MQTT to the fan only. Tutorial is here https://github.com/rickybrent/433toMQTTto433_ESP8266/wiki/Flower-Angel-18R-ST6