title: Get contact list and check if contacts have app installed like WhatsApp does
body: <p>I'm working on an app that creates an user profile. I need to be able to see who from my contacts has the app installed so that i am able to grant them access to my profile and see their profiles. </p>
  
  <p>How do i get the full contact list, determine my phone number to create my account with it, and check how many people from the contacts have the app installed? (similar to how WhatsApp does it)</p>
  
  <p>I know it's possible to get the contact list by using Apple API's, but do i have to send all the information to the server to check if they have the app installed? </p>
  
  <p>Thank you.</p>