ownCloud

The platform lets users store files, contacts, calendars and other data on a server they control, keeping the same information synchronized across multiple devices. It provides web‑based interfaces for viewing, editing and sharing those items, with optional encryption for transport and at‑rest protection. A modular app ecosystem adds functionality such as mail, news, and collaborative editing through integrations like OnlyOffice or Microsoft 365.

It is aimed at individuals, small groups and larger organizations that need on‑premises or hybrid file‑sync and sharing with strict data‑governance requirements. The software is released under the AGPL‑3.0 license, offers a free tier without subscription, and can be installed on‑site or in a private cloud. Its design separates storage, backend and frontend components via secure APIs, supporting multi‑factor authentication and fine‑grained access controls.

The core product is stable and widely used, with a community of over 200 million users worldwide. Documentation covers installation, development, and contribution guidelines, while support channels include forums, IRC, and social media. The extensible architecture allows integration of additional services and custom workflows while maintaining full ownership of the data.