For anyone looking for a free generator monitoring solution this project may be of interest to you:
The project requires some setup but there is no recurring fee since the solution uses an existing wifi for wired network connection. If you are not comfortable setting up the hardware there is one person providing pre-assembled units on ebay (the link is on the main project page).
This project supports Generac Nexus, Evolution residential controllers as well as H-Panel and G-Panel industrial controllers. In addition this project supports several features that are not available in most other monitoring solutions such as fuel consumption calculation and a variety of notification methods.