MacOS Contacts in Emacs
(Note that this works only on emacs-28, which is not yet released)

Following code in your startup file will enable macOS contacts access via built-in EUDC feature of Emacs. No need for any extra package for this. The below snippet will add a keyboard short-cut as well ‘C-c TAB’.

(when (eq system-type 'darwin)
		  (eval-and-compile (require 'eudcb-macos-contacts))
		  (eudc-macos-contacts-set-server "localhost"))
		  (eval-when-compile (require 'message))
		  (define-key message-mode-map
		  [(control ?c) (tab)] 'eudc-expand-inline)
		  (eval-when-compile (require 'sendmail))
		  (define-key mail-mode-map
		  [(control ?c) (tab)] 'eudc-expand-inline)
		

So if you are in a message buffer address field, just type few characters to search and then press the above defined key sequence ‘C-c TAB’. If multiple matching contacts are found then the completion system will come into play. Icomplete also works with it.

Another 0.1 sec saved in loading time. ‘esup’ now shows 1.497sec. Because this is all builtin.