I need to make a POST request to an external server from my webpage using Javascript. The body and response are both json. I can\'t figure out how to make this call or what tool
Are you the owner of the destination of the call? If yes, implement the CORS headers in server-side.
If no, you can fiddle using JSONP (it bypasses CORS) or you can even implement a server-side proxy that you own to route external requests (and of course, implement CORS there).
Check out the article on CORS in MDN if you want more information : HTTP access control (CORS) on MDN