Nextcloud

Nextcloud is the heavyweight of self-hosted file platforms: file sync with desktop and mobile clients, sharing links, calendars, contacts, and an app store that bolts on everything from office editing to talk.

The flexibility has a cost. A default install can feel sluggish, and getting it fast means caring about PHP tuning, Redis caching and a proper database. Some seasoned self-hosters run it lean with most apps disabled.

• Best-in-class sharing and external collaboration.
• Clients for every platform you are likely to own.
• Plan real time for initial setup and upgrades.

Pick it when you need a Dropbox-and-then-some for a family or team; pick Syncthing instead if you only need sync.