It depends a lot upon what format the other API needs. Will it accept one large XML or JSON blob, or so you need to split up separate requests and POST or PUT a separate request for each computer, or each property, or each property result, including some piece of the data in the POST?
For something that could be that complex I’d avoid using curl, and instead use whatever scripting or programming language with which you are most comfortable. For me that would be Python, but PowerShell, JavaScript, VBscript, C++…pretty much any modern language has support for HTTP and REST operations.