I use Homebridge along with Homebridge Nest to bridge my Nest devices to Home Assistant. Namely, this is used to bridge my Nest X Yale lock to Home Assistant.

Installation

There are a number of ways to install Homebridge but it should importantly be on the same network segment as the IoT devices it will talk to. It is possible to set up an mDNS repeater and firewall rules to keep them on separate network segments, but I chose to create a new LXC CT on my IoT VLAN instead to simplify the setup.

Homebridge can be installed easily using a variety of methods (documented on their Github) but since I don't have a Docker host on my IoT VLAN I decided to go ahead and install it in a new Debian CT using these instructions.

With that done, I opened the Homebridge UI to perform basic setup and then searched for homebridge-nest on the Plugins page to find Homebridge Nest. I installed it and configured authentication using the Google account "Cookie" method documented on the README on their GitHub page. I also set the HomeAway.Disable feature option since Home Assistant provides this functionality. After confirming that the Nest devices were loaded correctly in the logs on the Status page (the Plugin Logs option in the overflow menu of the plugin on the Plugins page is helpful for diagnosing failures) I went to the Integrations page in Home Assistant to add Homekit. It was detected by Home Assistant automatically so I just needed the pairing code from the homebridge Status page and then it imported the devices.