Concepts & Design
This page explains how the Homebridge Google Smart Home plugin allows Google Assistant to control your devices.
Consider the image below which shows the process flow for a request coming from Google Assistant. Unlike Apple HomeKit; Google Smart Home depends on a "Developer Cloud" on the internet to broker the connection to the end user's devices.
In the case of the Homebridge Google Smart Home plugin the "Developer Cloud" shown in the image below is provided by the homebridge-gsh.iot.oz.nu service which is owned and operated by the owner of the project. The "Devices" shown in the image below is your own local Homebridge instance running the homebridge-gsh plugin.
The Google Smart Home Action is published in the Google Assistant library and allows you to connect your Google Home to Homebridge. For further information please see the following reference material: