FreeFileSync is a free backup software that helps you to compare and synchronize files and folders on Windows, Linux and macOS. It is designed to save your time setting up and running backup jobs while having nice visual feedback along the way.
AJC Directory Synchronizer makes it easy to synchronize files and compare folders between any two locations. Synchronize large numbers of files between computers, sync laptop to desktop, mirror to backup drive, sync mp3 player etc.
A free and open source Java based file synchronization tool
Upload and download files and synchronize directories easily with Auto FTP Free. Automate file transfers, transfer only files of a certain type or based on modification date. Schedule transfers to happen automatically!
Komparator is an application that searches and synchronizes two directories.
Pieces of Flare is an Eclipse Plugin which allows (J2EE) developers to synchronize source directories.