Getting a List of Devices

So if I want to monitor all the devices in the system, since CoreAPI isn’t available, I assume the only way is to install a smartapp and have it so you have to select all the devices you want to monitor?

There should be an easier way to access all installed devices where a smartapp is installed and interact with them?

Any help would be greatly appreciated.

Monitor in what way? http calls from a webpage?
The “things” panel gives you a certain overview of the device states in one glance.

Monitor in the sense of reporting changes to a third party system all at once.

For example building a json object of all current device states and pushing (or pulling) that to another system for parsing and integration.