Nextcloud

Nextcloud is a self-hosted, open-source content collaboration platform developed by Nextcloud GmbH, headquartered in Stuttgart, Germany. It provides file sync and share across Windows, macOS, Linux and mobile, plus an integrated office suite (Collabora/OnlyOffice), Talk video conferencing, calendar, mail and groupware. Granular sharing, WebDAV access and strong authentication (TOTP, WebAuthn, OAuth2) make it a common alternative to Microsoft 365 and Google Workspace for organisations that need data sovereignty. The server is AGPL-licensed and free to self-host; commercial support and the Hub bundle are sold to enterprises and the public sector.