Sage50 integration

Hi I’m in the process of getting software integrated with sage50 , however they have some questions: Connection to your Sage50 instance
Is there a public API available (Sage50 cloud?) If yes:
what are the specific connection details? XML? JSON? Authentication? URL
how do we POST to it?
What are responses back from it?
Is there a duplicate, sandbox or testing environment we can develop to?
Can anyone assist with these questions ?