FreeFileSync does not support FTP directly. But the FTP functionality can be easily integrated by mapping the FTP webspace to a drive letter:
Example: Use the free utility NetDrive (http://www.netdrive.net)
Add a "New Site" and specify site name, site URL, drive letter, account and password.
Use the newly created drive as if it were a regular hard disk.
Note:
Most FTP drives set
a file's timestamp to the current time when synchronizing ignoring
the source file's time and date. As a workaround you can do a
"compare by filesize"; see corresponding section.