Home Assistant can be integrated with FreshTomato. This allows you to track/monitor devices connected to the FreshTomato router. Currently, there are two known implementations of HA-FreshTomato integration.

The first implemenation is on the Home Assistant website. See this page to configure a basic setup:

https://www.home-assistant.io/integrations/tomato/

However, before using this implemenation, you should be aware of a large limitation.

Excerpted from the webpage:

This particular Tomato integration allows one to track devices which are connected to a wireless router that is running Tomato as firmware.

Because of a limitation in Tomato’s API, this integration will only track wireless devices.

This integration is confirmed to be working with FreshTomato 2020.8

The github page containing the Home Assistant source code for Tomato integration can be found here: https://github.com/home-assistant/core/tree/dev/homeassistant/components/tomato

Note that, at the time this wiki entry was written,

An alternative that may function better in many cases is ha-freshtomato https://github.com/mx5gr/ha-freshtomato