Nextcloud

Nextcloud forked from ownCloud in 2016 and has since become the default answer to "self-hosted Google Drive" — but it has grown well past file sync into a full collaboration suite. Beyond desktop, mobile, and web sync clients with fine-grained sharing (expiring links, password protection, upload-only folders), a stock Nextcloud install can also run Nextcloud Office (a Collabora-based document editor), calendar and contacts sync, and Talk, its built-in chat and video calling app — genuinely replacing several separate SaaS subscriptions with one self-hosted deployment.

The ecosystem is the other reason Nextcloud dominates this space: a decade of continuous development has produced an app store with 200-plus community-built extensions, covering everything from two-factor auth providers to full CRM and forms tools, on top of core features like ransomware detection and automatic file versioning.

The trade-off for all that breadth is operational complexity. A production Nextcloud install typically wants Redis for caching, a working cron job for background tasks, and — if you want real-time document editing — a separate Collabora or OnlyOffice container, which is more moving parts to patch and monitor than a single-purpose sync tool. Some enterprise-grade features, like advanced server-to-server federation and compliance reporting, are reserved for Nextcloud GmbH's paid Enterprise subscription rather than the free AGPL-3.0 core. And under very large file counts, the web UI can feel slower than Seafile's, which was built with sync performance as its primary focus. For teams that want one self-hosted platform instead of five separate tools, Nextcloud remains the broadest and most mature option.