ASynK CmdLine is a powerful open source Contacts synchronization program that works with a variety of Contacts software such as Microsoft Outlook, Microsoft Exchange Server, Google Contacts, Any standards compiant CardDAV server, and Emacs BBDB.

Some of the key features of ASynK are:

  1. ASynK allows two-way sync of Contacts across any two supported sources. For e.g. you can use this to copy contacts from one Google account to another, or from your Google account and your official MS Exchange account etc.
  2. ASynK is the only two-way synchronization option for BBDB known to be in existence today. So if you are keen to keep your BBDB content synchronized with a mobile device or Outlook, look no further.
  3. ASynK works on Windows, MacOS X, and Linux. Outlook synchronization only works on Windows.
  4. Synchronization is granular to the level of 'Folders', i.e. you can synchronize one folder of Google Contacts with a Outlook folder (on Windows at work, say), and another Google folder in the same account with BBDB (On your Mac, say)
  5. The infrastructure is there to add more database and item types (i.e. tasks, notes, etc.), but currently only Contacts synchronization is supported
  6. It is free software, and released under the GNU AGPL (Affero GPL) version 3