OwnCloud (stylized ownCloud) is a suite of client-server software for creating file hosting services and using them. OwnCloud is functionally quite similar to the widely used Dropbox, with the primary functional difference being that OwnCloud is free and open-source, and thereby allowing anyone to instal and operate it without charge on a private server. It additionally supports extensions that allow it to work like Google Drive, with online document editing, calendar and contact synchronization, and more. Its openness eschews enforced quotas on storage space or the number of connected clients, instead having hard limits (like on storage space or number of users) defined only by the physical capabilities of the server.
Frank Karlitschek, a KDE software developer, announced the development of OwnCloud in January 2010, in order to provide a free software replacement to proprietary storage service providers. The company was founded in 2011.
OwnCloud Inc., the company founded by Karlitschek, has attracted funding from investors, including an injection of 6.3 million US$ in 2014.
In April 2016 Karlitschek and six contributors left OwnCloud Inc., resulting in the closure of OwnCloud's U.S. operations. The departing developers forked the OwnCloud code to start a new project called Nextcloud.
In July 2016 ownCloud GmbH, based in Nuremberg Germany, secured additional financing, with the investors taking a majority share, and expanded its management team.
In order for desktop machines to synchronise files with their OwnCloud server, desktop clients are available for PCs running Windows, OS X, FreeBSD or Linux. Mobile clients exist for iOS and Android devices. Files and additional data (such as calendars, contacts or bookmarks) can additionally be accessed, managed, and uploaded using a web browser without any additional software. Any updates to the file system are pushed to all computers and mobile devices connected to a user's account.
Encryption of files might be enforced by the server administrator.
OwnCloud files are stored in conventional directory structures, and can be accessed via WebDAV if necessary. User files are encrypted both at rest and throughout transit. OwnCloud can synchronise with local clients running Windows (Windows XP, Vista, 7 and 8), OS X (10.6 or later), or various Linux distributions.
From the administration perspective, OwnCloud permits user and group administration (via OpenID or LDAP). Content can be shared by defining granular read/write permissions between users and/or groups. Alternatively, OwnCloud users can create public URLs when sharing files. Logging of file-related actions is available in the Enterprise and Education service offerings.
Furthermore, users can interact with the browser-based ODF-format word processor, bookmarking service, URL shortening suite, gallery, RSS feed reader and document viewer tools from within OwnCloud. For additional extensibility, OwnCloud can be augmented with "one-click" applications and connexion to Dropbox, Google Drive and Amazon S3.
OwnCloud server and clients might be downloaded from the OwnCloud website and from third-party repositories, such as Google Play and Apple iTunes, and repositories maintained by Linux distributions. In 2014, a dispute arose between OwnCloud and Ubuntu regarding the latter allegedly neglecting maintenance of packages, resulting in the temporary removal of OwnCloud from the Ubuntu repository.
OwnCloud has been integrated with the GNOME desktop. Additional projects that use or link to OwnCloud include a Raspberry Pi project to create a cloud storage system using the Raspberry Pi's small, low-energy form-factor.
In addition to the standard open-source packages, an Enterprise version of OwnCloud is additionally sold, aimed at businesses which require advanced features and software support.