No, on-premise sadly has no API, and my best guess is it never will. But you can interact with the SQL/Express server directly. I do this for multiple reasons:
I have integrated it into my in-house helpdesk tool to pull computer assets for users
I have created a self-service deployment tool which lets users deploy software themselves using lansweeper. It presents them with a (filtered) deployment list and with 2 clicks they can start a deployment to their computer.
To get started, their database docs help a lot. If you have specific question feel free to reach out to me.