How do apps like Skype show caller IDs in the native iOS recent calls list when a user isn't a contact in Swift?

Question

I've noticed that many apps like Skype, Slack, Telegram etc, are able to show the ID of contacts saved within those apps in my native iOS recent calls list as if they are existing contacts.

Here's a great example I found in a Google search:

I currently manually store and manipulate contacts to get this same effect for an app I'm currently working on. It's a bit messy and I'm wondering if I can somehow achieve what all of these apps achieve?

I've searched around but I'm not sure where I should be looking. The CNContactStore class doesn't mention anything about this.

How can do this, or where should I be looking to learn how to do it?

Answer 1

Paulw11's comment was the answer to my question:

They report the name via a CXCallUpdate when they report the incoming call. If your app isn't a voip app then you can create a callkit directory extension github.com/paulw11/CallKitTutorial