How to HTTPS call for Mailgun mail services (update)

Question

I need to use mailgun api in objective-c Mac OS X. I did try different solution without success. A possible solution I think is to convert the cUrl call with NSURL. so any help for achieve this is largely valued. thanks for your time

 curl -s --user 'api:key-0000000000000000000' \
 https://api.mailgun.net/v3/sandbox000000000000000.mailgun.org/messages \
 -F from='Excited User <[email protected]>' \
 -F [email protected] \
 -F [email protected] \
 -F subject='Hello' \
 -F text='Testing some Mailgun awesomness!'