Sync the macOS or OS X Contacts App with the Disroot cloud.
This will allow you to check, update and remove your contacts from any computer with an internet connection. Also it will enable syncing contacts with your smartphone and/or tablet. Once it runs, and nothing breaks, you'll forget it is there.
A window opens called 'Add CardDAV account'
Use these settings:
Account type: Advanced.
Username: your username (without @disroot.org)
Password: your password
Server Address: https://cloud.disroot.org
Server Path: /remote.php/dav/principals/users/USERNAME/
(replace USERNAME with your username)
Port: 443
and Use SSL ticked.
For systems before macOS Mojave these settings should work:
Account type: Advanced.
Username: your username (without @disroot.org)
Password: your password
Server Address: cloud.disroot.org
Server Path: /remote.php/dav/addressbooks/users/USERNAME/contacts/
(replace USERNAME with your username)
Port: 443
and Use SSL ticked.
Click Sign In
!
Now your contacts are added. If you now open the Contacts App, cloud.disroot.org will show in the left column. You can change the name in the Contacts App preferences or in the System Preferences.
Any contacts you now add will be synced automagically to the Disroot servers.
(ps. these steps are virtually the same on iOS)