The Integration System gives you many options for interfacing programmatically with the backend.
Before you do, though, you'll need an API Key and the endpoint!
To access the API, you will need an API key. You can create an API Key in the /backend area of your portal. API Keys are managed in Settings -> API Keys
Once you have an API Key, you can access the API through the "api" folder on your portal's url.
For example: https://yourportal.example.com/api/v1/portal/upgrade?apikey=my_api_key_here
All of the Integration System's APIs return JSON. You can convert this easily to an array in most languages. (json_decode, for example, in PHP)