Seafile stores files on a central server that can be synchronized with personal computers and mobile devices. The self-hosted version is free and open-source, the hosted version is free for up to three users.
Also see Seatable.
Ranked in these QuestionsQuestion Ranking
Pro Free and open source
Seafile community edition is licensed under GPLv2 with source code available on GitHub.
Pro Client-side encryption
All files are transferred with AES 128 bit encryption.
Con Requires maintenance
You have to manually keep the server and clients up to date.