Nextcloud is a suite of client-server software for creating and using file hosting services. Nextcloud application functionally is similar to Dropbox that can be installed on-premise. Nextcloud is free and open-source, which means that anyone is allowed to install and operate it on their own private server devices.
Nextcloud has many functionalities can be added as extensions, including: calendars (CalDAV), contacts (CardDAV), streaming media (Ampache), browser-based text editor, bookmarking service, gallery, document viewer tools from within Nextcloud, connection to Dropbox, Google Drive and Amazon S3. The most interesting feature is the Nextcloud Talk, which is an extension that provides a Whatsapp-like chatting service on mobile and desktop platforms.