I would like to have a survey log into another computer system to perform a Get statement and pull information into a survey. It would likely involve establishing a secure connection. Can this be done with custom support? I can give you more details if you wish.
I am not certain about logging into another system, but I do know you can use php/mysql along with the HTTP Connect to both GET and POST data.
As far as API’s, I am uncertain as I have not worked with them.