Nextcloud

Nextcloud provides a self‑hosted platform for storing and synchronising files, contacts, calendars, email and a wide range of additional data types. Users can access their information from desktop, mobile and web clients, and keep it consistent across devices through built‑in sync mechanisms. The system supports sharing with others, allowing fine‑grained permissions and collaborative workflows.

The core server is extensible via an app store that offers hundreds of optional components, such as video‑chat, online office editing, workflow automation and structured data tables. These apps integrate into a unified interface, enabling teams to combine file management, communication and productivity tools without relying on external services.

Security features include server‑side encryption, two‑factor authentication and a public vulnerability bounty program. The software is released under the AGPL‑3.0 license, can be installed on personal hardware, hosted by providers, or run on dedicated appliances, and is positioned as an open‑source alternative for private‑cloud collaboration.