HI there, I'm Dave. I am an experienced web developer and NetSuite developer as well.
For web applications, I mainly use PHP, Codeigniter, Wordpress, jQuery, Bootstrap. As a NetSuite developer, I have 3 to 4 years experience (up to present) using NetSuite.
Based on your initial description of the requirements, my solution would be to create a RESTlet which searches for the internal ID and custom fields. PHP script will read the result of the RESTlet and process the data accordingly.
Have a nice day!