File sync is one of the oldest self-hosting use cases. The leaders are mature, with desktop and mobile apps that sync like Dropbox.
1
server nextcloud/server
Files plus calendar, contacts, office documents and video calls: a whole collaboration suite around file sync. AGPL-3.0.
2
seafile haiwen/seafile
Focused on fast, reliable file sync, with file properties and views for organising content.
3
ocis owncloud/ocis
ownCloud Infinite Scale, a rewrite of ownCloud in Go without a separate database. Apache-2.0.
How to choose
A full Google Workspace-style suite: Nextcloud. Pure file sync that is fast with large libraries: Seafile. A modern, simpler deployment: ownCloud Infinite Scale.
How we pick: we start from every public GitHub repository with 1,000+ stars, keep the projects that do the job in the title, and read their descriptions and licenses. Stars show community size, not quality, so we also show maintenance status. Nobody paid to be listed.