isync is a commandline application which synchronizes a local maildir-style mailbox with a remote IMAP4 mailbox, suitable for use in IMAP-disconnected mode. Multiple copies of the remote IMAP4 mailbox can be maintained, and all flags are synchronized. TLS/SSL is supported via imaps: or STARTTLS.

Sync is a software application published by Apple Computer. It runs only under Mac OS X and is used to synchronize data in i Cal and the Address Book with .Mac and with devices including i Pods, many Sync ML-compatible mobile phones and with Palm OS handheld organizers & smartphones (but not Pocket PCs). Prior to the release of Mac OS X 10.4, iSync could also synchronize a user's Safari bookmarks with the .Mac subscription service provided by Apple.